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THE 


PALJIONTOGRAPHICAL   SOCIETY. 


INSTITUTED  MDCCCXLVII. 


LONDON: 

MDCCCLXIV — MDCCCLXXXII. 


THE    CRETACEOUS    ECHINOIDEA. 


DIRECTIONS   TO   THE   BINDER. 


The  Monograph  on  the  Cretaceous  Echiaoidea  will  be  found  in  the  Volumes  of  the  Palaeontographical 
Society  for  the  years  1862,  1867,  1869,  1870,  1872,  1873,  1875,  1878,  1881,  and  1882. 

Cancel  the  Title-pages  affixed  to  the  separate  parts,  and  substitute  the  general  Title-page  provided  in 
the  Volume  for  the  year  1882. 


ORDER  OF  BINDING  AND   DATES   OF  PUBLICATION. 


PAGES 

PLATES 

ISSUED  IN  VOL. 
rOB  TEAB 

PUBLISHED 

Title-page,  Contents,  i — xviii 

I-III,  IIIa,  IV— VII,  VIlA,  VIII 

1882 

June,  1882 

1—64 

— 

1862 

August,  1864 

65—112 

IX,  X 

1867 

June,  1868 

— 

XI 

1862 

August,  1864 

— 

XII— XXI,  XXIa,  XXIb 

1867 

June,  1868 

113—136 

XXII— XXIX,  XXIXa,  XXIXb 

1869 

January,  1870 

137—160 

XXX— XXXIX 

1870 

January,  1871 

161—184 

XL— XLIV 

1872 

October,  1872 

185—224 

XLV— LII 

1873 

February,  1874 

225—264 

LIII— LXII 

1875 

December,  1875 

265—300 

LXIIa,  LXIIl— LXIX 

1878 

March,  1878 

301—324 

LXX-LXXV 

1881 

May,  1881 

325—371 

LXXVI— LXXX 

18S2 

June,  1882 

K^.^' 


monog:raph 


Yx     I  ON   THE 


jtJU 


BRITISH    FOSSIL 


ECHINODERMATA 


FROM 


THE    CRETACEOUS    FORMATIONS. 


THOMAS  WRIGHT,  M.D.,  F.R.S.,  F.G.S., 

VICE-PRESIDENT  OP  THE  PAL«0NT0QRAPH1CA.L  SOCIETY  ;  CORRESPONDING  MEMBER  OP  THE   ROYAL  SOCIETY   OF    SCIENCES 

OF   Ll:fiGE  ;   THE   SOCIETY  OF  NATURAi  SCIENCES  OP  NEUCHATEl,;    VICE-PRESIDENT  OF  THE  COTTESWOLD 

naturalists'    FIELD   CLUB;    CONSULTING    SURGEON    TO    THE    CHELTENHAM    HOSPITAL; 

AND  MEDICAL  OFFICER  OF  HEALTH  TO  THE  URBAN  SANITARY  DISTRICTS 

OF   CHELTENHAM,    CHARLTON    KINGS,   AND    LECKHAMPTON. 


VOLUME    I.— THE    ECHINOIDEA. 


LONDON: 
FEINTED    FOK   THE    PALiEONTOGKAPHICAL    SOCIETY. 

1864—1882. 


PEINTBD   BY 
J.  E.  ADLARD,    BAUTHOLOMEW    CLOSE. 


CONTENTS. 


Preface  .... 

Retrospect  .... 

History  of  Echinology  since  1862 

Bibliography  of  ditto 

Divisions  of  the  Cretaceous  Formation  in  England 

Classification  of  the  Echinodermata 

Terminology  of  the  Component  Elements  of  the  Test  of  the  Echinoidea 

Classification  of  the  Echinoidea,  Endocyclica  and  Exocyclica 

Description  of  the  Families,  Genera  and  Species  of  the  British  Cretaceous 

Echinoidea    .......  35 — 342 

Summary  of  ditto  ......  345 — 359 

Range  in  Geological  Time  of  ditto  .....     360 

Index    ........  361 — 371 


PAGE 

.     i,  ii 

.  iii,  iv 

iv — sii 

xiii — xviii 

1—14,  343,  344 

15—20 

21—28 

29—34 


PREFACE. 


With  this  Preface  the  history  of  the  British  Fossil  Cretaceous  Bchinoidea  is 
brought  to  a  close,  and  it  only  remains  for  the  Author  to  record  his  warmest 
acknowledgments  to  the  many  kind  friends,  enumerated  in  the  retrospect,  who 
have  generously  assisted  him  in  his  long  and  laborious  task.  The  duty  imposed 
upon  him  by  the  Council  of  the  PaliEontographical  Society,  occasioned  by  the 
untimely  death  of  his  distinguished  colleague,  Prof.  Bdw.  Forbes,  F.R.S,,  has 
been  much  lightened  by  their  ready,  willing,  and  friendly  aid  at  all  times. 

When  the  Plates  for  this  Monograph  had  been  nearly  completed  his  accom- 
plished artist,  Mr.  Charles  Bone,  who  had  assisted  him  during  so  many  years,  like- 
wise passed  away ;  so  that  in  writing  this  preface  the  Author  is  solemnly  reminded 
of  the  mutability  of  all  human  undertakings,  and  desires  to  express  his  deep  regret 
that  one  who  had  aided  him  for  nearly  thirty  years  by  steady,  continiious,  and 
most  accurate  work,  had  not  been  spared  to  see  the  conclusion  of  his  labours. 
The  Author,  therefore,  embraces  the  present  opportunity  of  recording  his  high 
appreciation  of  Mr.  Bone's  artistic  drawings,  which  for  beauty  and  accuracy  in 
lithographic  art  have  not  been  surpassed,  whilst  all  essential  details  relating  to  the 
anatomical  structure  of  the  Echinoidea  have  been  faithfully  rendered  throughout. 

The  Author  in  an  especial  manner  desires  to  return  his  warmest  acknowledg- 
ment and  very  best  thanks  to  his  old  friend  the  Rev.  Professor  Wiltshire,  F.G.S., 
the  indefatigable  Secretary  of  the  Palteontographical  Society,  for  his  unwearied 
attention  to  every  part  of  his  work  as  it  passed  in  successive  years  through  the 
press.  The  admirable  summary  of  the  British  Cretaceous  Echinoidea  and 
copious  index  which  he  has  kindly  contributed  to  complete  this  volume,  have  added 
much  to  its  value  and  general  usefulness  ;  and  he  must  further  add  that  the  liberal 


11 


PREFACE. 


supply  of  fine  specimens  from  his  rich  collection  of  Chalk  Echinoderms,  in  order 
to  furnish  the  artist  with  the  best  possible  specimens  for  the  plates,  has  been  of 
very  great  assistance  in  carrying  out  the  work,  and  for  which  he  now  expresses 
his  deep  obligations,  and  records  his  lasting  gratitude  for  all  his  most  kind, 
generous,  and  friendly  aid  from  first  to  last. 


4,  St.  Maegaeet's  Teeeace,  Cheltenham  ; 
25th  April,  1882. 


A    RETROSPECT. 


Before  bringing  this  Monograph  to  a  termination  I  desire  to  state  to  my  Readers 
(many  of  whom  have  joined  our  Society  since  the  work  was  commenced),  the  circumstances 
under  which  I  became  the  historian  of  the  British  Cretaceous  Echinodermata,  and 
the  difficulties  I  experienced  and  had  to  overcome  during  the  progress  of  its  composi- 
tion, as  they  help  to  explain  the  apparent  delay  that  has  occurred  and  the  length  of  time 
which  has  elapsed  between  the  issue  of  the  first  and  last  part  of  the  Monograph. 

When  the  History  of  the  British  Fossil  Echinodermata  was  first  proposed  to  the 
Council  of  the  Palseontographical  Society  in  1851,  by  the  late  Professor  Edward  Eorbes, 
it  was  arranged  that  the  description  of  the  Cretaceous  species  was  to  be  undertaken  by 
him,  and  that  of  the  Jurassic  species  by  myself.  Long,  however,  before  the  Jurassic 
portion  was  complete  my  highly  esteemed  and  learned  colleague  died  (in  November, 
1854),  very  soon  after  he  had  attained  the  object  of  his  life's  ambition,  the  Chair  of  Natural 
History  in  the  University  of  Edinburgh.  Before  leaving  London,  Professor  Eorbes  had 
gathered  from  various  sources  a  large  collection  of  materials  for  the  Cretaceous  Mono- 
graph ;  these  he  took  with  him  to  Edinburgh,  intending  to  commence  the  work  as  soon  as 
he  had  settled  down  into  the  routine  duties  of  his  new  chair ;  but  his  sudden  death 
unfortunately  deprived  science  of  the  rich  store  of  facts  and  notes  on  the  specimens  he 
had  collected  from  various  cabinets  for  this  work.  Under  these  painful  circumstances 
the  Council  of  the  Palseontographical  Society  urged  me  to  undertake  the  description  of 
the  Cretaceous  forms  as  soon  as  I  had  finished  the  Jurassic  species  ;  and  this  I  consented 
to  do  in  the  belief  that  the  materials  collected  by  Professor  Eorbes  would  be  available  for 
the  work.  On  making  inquiry,  however,  I  found  to  my  dismay  that  after  the  death  of 
my  friend  the  fossils  had  been  packed  up  with  other  property  and  sent  into  the  cellars 
of  the  University,  and  could  not  be  touched  until  some  legal  matters  were  arranged.  A 
long  delay  now  took  place ;  and  at  last,  when  a  search  was  made,  the  cases  containing 
the  Cretaceous  specimens  of  Echinides  could  not  be  found.  In  this  dilemma,  and  not 
then  having  a  good  collection  of  Chalk  Urchins  myself  (all  my  energies  up  to  that  time 
having  been  given  to  complete  my  Jurassic  collection),  I  applied  to  the  authorities  of 
the  British  Museum,  to  the  Director  of  the  Museum  of  Practical  Geology  (the  late  Sir 
Roderick  Murchison) ;  and  to  the  Earl  of  Ducie,  the  Rev.  Thos.  Wiltshire,  the  late  Dr. 
Bowerbank,  the  late  Professor  Tennant,  the  late  Dr.  S.  Woodward,  Mr.  W.  Cunnington, 

b 


iv  BRITISH  FOSSIL   ECHINODERMATA. 

Major  Cockburn,  Mr.  Caleb  Evans,  Mr.  Robert  Etlieridge,  and  Mr.  Weist.  Messrs.  E.  T. 
Newton  and  Sharman,  Assistant  Naturalists  of  the  Jerrayn  Street  Museum,  most  kindly  at 
all  times  aided  me  in  making  selections  of  specimens  for  figuring  in  the  plates. 

On  the  Continent  I  have  had  much  friendly  aid  from  MM.  Gustave  Cotteau,  of 
Auxerre,  Perceval  de  Loriol,  of  Geneva,  Herr  Struckmann,  of  Hanover,  Professor  De 
Koninck,  of  Liege,  and  the  late  MM.  Seemann  and  Triger,  of  Paris. 

In  addition  to  the  valuable  aid  of  the  above  kind  friends,  to  vi^hom  individually  and 
collectively  I  tender  my  warmest  thanks,  I  have  made  many  tours  of  inspection  to  all 
the  best  private  collections  in  England  containing  Chalk  Echinoderms,  and  have  visited 
and  worked  the  quarries  in  the  different  Cretaceous  formations,  in  order  to  identify  the 
distribution  of  the  species  with  the  beds  from  whence  they  were  said  to  have  been 
collected.  All  these  proceedings  have  occupied  much  time,  and  were  undertaken  at  a 
period  when  I  was  fully  occupied  in  the  laborious  practice  of  my  profession,  so  that  I  found 
much  difficulty  in  bringing  out  the  parts  consecutively  in  the  annual  volumes  of  the 
Palseontographical  Society. 

The  many  duties  and  incessant  occupation  connected  with  my  present  position  as 
Medical  Officer  of  Health  having  deprived  me  of  the  leisure  necessary  to  continue  my 
sketch  of  the  History  of  Echinology,  I  ventured  to  ask  my  much  esteemed  friend,  M. 
Perceval  de  Loriol  (author  of  the  '  Echinologie  Helvetique  ')j  to  undertake  this  portion  of 
the  work.  Monsieur  de  Loriol,  with  his  usual  kindness,  consented  to  do  so,  I  have, 
therefore,  now  the  pleasure  of  introducing  his  masterly  sketch  (for  the  translation  of 
which  I  alone  am  responsible)  of  the  progress  made  in  Echinology  during  the  last  twenty 
years.  For  this  most  valuable  addition  to  my  work  I  beg  to  return  my  highly  accom- 
plished friend  my  very  warmest  thanks. 


"  On  the  History  of  Echinology  since  1863,  by  Perceval  de  Loriol. 

The  fourth  part  of  the  vast  Monograph,  undertaken  by  Dr.  Wright,  relating  to  the 
description  of  the  Jurassic  Echinides,  was  published  in  1861.  Dr.  Wright  had  enriched 
that  part  with  a  Table,  giving  a  list  of  the  works  concerning  the  Echiuides,  that  had 
come  to  his  knowledge  up  to  that  date.  It  will  not  be  without  interest  and  utility, 
therefore,  to  terminate  the  Monograph  on  the  Cretaceous  Echinides,  to  which  Dr.  Wright 
is  now  adding  the  last  pages,  with  a  rapid  review  of  the  progress  which  has  been  accom- 
plished during  the  last  twenty  years  in  the  domain  of  Echinology,  and  to  take  a  glance  at 
the  magnificent  discoveries  for  which  we  are  indebted  to  the  late  Expeditions,  which 
had  for  their  object  the  investigations  of  the  depths  of  the  sea. 


A  RETROSPECT.  v 

Dr.  Wright's  numerous  professional  occupations  not  permitting  him  to  enter  upon 
this  branch  of  the  subject,  he  has  asked  me  to  take  it  upon  myself,  and  it  is  with  very 
great  pleasure  that  I  embrace  the  occasion  of  co-operating,  in  however  feeble  a  degree, 
in  a  great  and  beautiful  work,  brought  so  happily  to  a  conclusion  by  my  learned 
friend. 

Commencing  with  an  enumeration  of  the  many  works  written  on  the  Fossil  Echinides, 
I  think  we  shall  proceed  with  more  method  if  they  be  grouped  by  countries  and  by 
regions,  taking  into  consideration,  not  the  nationality  of  the  authors,  but  the  Echinitic 
fauna  upon  which  they  have  made  their  observations.^ 

The  study  of  the  Eossil  Echinides  of  Great  Britain  appears  during  late  years  to  be 
concentrated  in  the  general  Monograph  by  Dr.  Wright,  and  I  find  myself  able  to  cite 
only  one  paper,  that  by  Mr.  Keeping  (1),  '  On  the  Genus  Pelanechinus,  a  new  Section 
established  for  the  Hemipedina  coraUina,  Wright,'  the  coronal  plates  of  which  appear  to 
have  been  in  some  measure  imbricated,  resembling  those  in  Asihenosoma. 

France  has  contributed  a  great  number  of  works  on  Echinology,  of  which  most  are 
due  to  the  indefatigable  zeal  and  untiring  industry  of  M.  Gustave  Cotteau,  of  Auxerre ; 
and  it  is  important  to  mention  above  all  a  work  of  the  first  order,  the  'Echinides 
de  la  Paleontologie  Fran^aise'  (2),  the  publication  of  which  is  still  being  actively 
carried  on. 

The  '  Elchinides  Cretaces,'  commenced  by  d'Orbigny  and  continued  by  M.  Cotteau,  is 
now  completed.  Two  volumes  of  the  'Echinides  Jurassiques '  have  already  appeared. 
They  comprise  the  Echinides  irregxdiers,  the  family  of  the  CidariDjE,  and  those  of  the 
Saleniad^  ;  those  of  the  DiadematidjE  will  soon  follow.  Three  other  very  important 
works  of  M.  Cotteau,  commenced  many  years  ago,  have  been  completed ;  the  description 
of  the  Echinides  of  the  Department  of  the  Sarthe  (3),  in  which  he  has  made  known  the 
Urchins,  so  numerous  and  varied,  which  the  Jurassic  and  Cretaceous  strata  of  this 
Department  contain,  and  the  illustrations  of  which  required  sixty-five  plates  ;  the  second 
part  of  the  '  Echinides  of  the  Yonne '  (4),  comprising  the  description  and  figures  of  ninety- 
nine  species  from  the  Terrains  Cretaces ;  and  lastly  the  first  series  of  new  or  little  known 
Echinides,  which  have  successively  appeared  in  the  '  Revue  et  Magasin  de  Zdologie '  (5), 
and  in  which  are  found  valuable  observations  upon  known  species,  as  well  as  the 
description  of  numerous  new  species,  the  most  part  derived  from  France,  but  also 
from  other  countries.  Independently  of  these  works,  as  a  whole,  M.  Cotteau  has 
published  many  local  Monographs,  which  have  made  great  steps  towards  an  exact  know- 

1  To  avoid  the  incumbrance  of  notes  I  shall  add  an  appendix  to  this  essay,  in  which  I  shall  give  the 
titles  of  the  works  to  be  identified  by  corresponding  figures  in  the  text.  I  have  not  cited  all  the  works  in 
which  Fossil  Echinides  are  mentioned,  but  only  those  which  appear  to  me  more  specially  important  either 
as  general  works  on  the  subject,  or  those  in  which  some  discovery  is  recorded.  To  this  end  I  have  made  as 
conscientious  an  investigation  of  all  the  works  as  was  in  my  power  ;  but  possibly  some  publications  may 
have  escaped  my  notice.  If  such  should  be  the  case  I  make  an  honorable  amende  in  advance  for  the 
omission  which  I  shall  be  the  first  to  regret. 


vi  BRITISH  FOSSIL  ECHINODERMATA. 

ledge  of  the  Ecbinitic  Fauna  of  France.  These  contributions  are  in  the  form  of 
notes,  or  lists  of  species,  with  observations  made  to  clear  up  critical  questions,  with 
sometimes  more  complete  studies  on  which  the  species  are  found  entirely  described  and 
figured.  M.  Cotteau  has  thus  made  known  successively  the  Nummulitic  Echinides  of 
Biarritz  (6) ;  the  Cretaceous  Urchins  of  Martigues  (7) ;  the  Echinides  of  the  Pyrenees 
(8)  ;  those  of  the  Aube  (9) ;  and  those  of  the  Oxfordian  of  the  Ard^che  (10) ;  new  species 
from  the  Environs  of  Bordeaux  (11);  the  Echinides  of  the  Cretaceous  Colony  of  the 
"  Garonnien"  of  the  Department  of  Aude  (12),  among  which  was  found  the  first  Cretaceous 
ScJdzaster  known;  those  of  the  Miocene  deposits  of  Corsica  (13) ;  those  of  the  Jurassic 
strata  of  Normandy  (14)  ;  and  lastly,  a  supplementary  note  (15)  completes  the  character- 
istics of  the  curious  new  genus  Tetracidaris,  from  the  Neocomian  of  Central  France, 
which  possesses  two  series  of  pairs  of  pores  in  each  poriferous  zone,  and  four 
series  of  inter-amubulacral  plates.  In  addition  to  these  beautiful  monographic  studies 
of  M.  Cotteau,  there  are  other  works  upon  the  Echinides  of  France,  which  still  remain 
to  be  enumerated.  Thus,  Saemann  and  Dollfuss,  in  1861,  characterised  with  care 
some  species  from  Trouville  (16).  Dumortier,  in  his  remarkable  work  upon  the  '  Depots 
Jurassiques  du  Bassin  du  Rhone,'  has  described  many  Echinides  from  the  Lias  (17). 
M.  Tournouer  (18),  has  given  a  revision  of  the  Echinides  of  the  Calcaire  a  Asteries 
(Tongrian)  of  the  South-west  of  France,  with  figures  of  new  species  and  critical  remarks 
on  the  same.  Caffin  (19)  has  occupied  himself  with  the  Echinides  of  the  Environs  of 
Evreux.  M.  Bucaille  (20)  has  given  a  Catalogue  Raissonne  of  those  of  the  Seine  Inf6- 
rieure,  with  descriptions  of  new  species.  Professor  Hebert  (21)  has  endeavoured  accu- 
rately to  diagnose  the  characters  of  certain  Hemiasters,  and  he  has  (22)  described  two 
new  Hemipneustes  from  the  Chalk  of  the  Pyrenees.  M.  Sauvage  (23)  has  made  known 
new  species  from  the  Upper  Jurassic  of  the  Boulonnais.  M.  Arnaud  (24)  has  endea- 
voured to  facilitate  the  determination  of  the  numerous  Cretaceous  species  of  the  genus 
Ci/phosoriia,  to  which  he  has  added  some  new  forms.  Desmoulins  (25),  to  whom 
Echinology  was  already  indebted  for  numerous  works,  has  made  some  interesting  obser- 
vations upon  six  species  of  Ecliinolampas,  upon  the  spines  of  Echinocidaris,  and  upon  a 
Miocene  Spatangus  from  Saucats.  Finally,  I  have  published  (26)  a  description  of  some 
Echinides  from  Berrias  and  Aizy  (27),  and  have  been  occupied  with  those  from  the 
Portlandian  of  the  Yonne  (28),  also  with  those  from  the  Upper  Jurassic  of  the  Bou- 
lonnais (29),  and  of  the  Haute  Marne  (30).  A  general  work,  by  Dujardin  and  Hupe, 
upon  the  Echinoderms  (31)  has  likewise  to  be  mentioned. 

In  Switzerland  the  Echinologic  studies,  to  which  Agassiz  and  Desor  had  already 
given  such  vigorous  impulsion,  have  been  continued.  Etallon  (32),  who  had  already 
studied  the  Echinides  from  diff'erent  formations  bordering  on  the  frontiers  of  France  (33 
and  34)  and  of  Switzerland,  aided  in  the  enlargement  of  a  posthumous  work  of 
Thurmann's,  'LeLethsea  Bruntrutana  '  (35),  in  which  numerous  species  of  Echinides  are 
found  described  and  figured.     M.  Ooster  (36)  a  few  years  afterwards  published  his 


A  RETROSPECT.  vii 

*  Synopsis  of  Fossil  Echinoderms  of  the  Swiss  Alps,'  in  which  numerous  species  from  the 
Nummulitic  formation  are  found  figured.  He  has  given  also  indications  of  certain  Alpine 
species  in  his  '  Protozoa  Helvetica'  (37).  I  have  described  also  some  Echiuides  from  the 
Neocomian  of  Mont  Saleve  (39),  from  the  Valangian  of  Arzier  (40),  and  the  Urgonian 
of  Landeron  (41).  I  have  also  undertaken,  under  the  title  of  '  Echinologie  Helvetique  ' 
(42),  the  publication  of  the  Fossil  Urchins  of  Switzerland.  In  the  First  Part  compre- 
hending the  Jurassic  Echinides  I  had  the  happiness  of  having  for  my  collaborator 
M.  Desor.  I  afterwards  finished  alone  the  Second  and  Third  Parts,  which  treat 
of  the  Cretaceous  and  Tertiary  Echinides.  Four  hundred  and  thirty-eight  species 
are  the  contingent  of  the  Echinitic  fauna  furnished  up  to  the  present  time  by  the  Secondary 
and  Tertiary  formations  of  Switzerland. 

Thanks  to  M.  Cotteau,  the  Fossil  Echinides  of  Belgium,  hitherto  known  in  a  very 
summary  manner,  have  been  submitted  to  a  new  and  very  necessary  revision.  He  has 
published,  in  succession,  a  '  Note  on  the  Cretaceous  Echinides  of  Hainaut '  (43),  with  some 
species  figured ;  the  '  Description  of  the  Echinides  of  the  Calcaire  Grossier '  of  Mons, 
Senonian  (44) ;  and  the  '  Description  of  the  Tertiary  Echinides  of  Belgium '  (45),  an 
important  Monograph,  in  which  thirty-one  species  are  found  figured  and  described,  and  of 
which  thirteen  species  only  were  previously  known,  and  the  most  of  these  very  imperfectly. 

It  is  likewise  to  M.  Cotteau  that  we  owe  the  knowledge  of  three  interesting  species 
from  the  Upper  Chalk  of  Sweden  (46). 

Among  the  works  which  have  appeared  on  the  Echinides  of  Germany  it  behoves  me 
to  cite,  in  the  first  place,  the  volume  on  the  '  History  of  Fossils  of  Germany,'  which 
Professor  Quenstedt  has  devoted  to  the  Echiuides  (47).  The  Atlas  of  twenty-eight 
plates  contains  no  less  than  1700  figures,  with  numerous  magnified  views;  whilst  the 
text  treats  of  not  only  the  Echinides  of  Germany,  but  also  many  others  which  are 
not  found  there.  This  work,  the  result  of  very  considerable  labour,  comprehends 
a  great  number  of  useful  indications  and  previous  observations  ;  but  it  is  to  be  regretted 
that  Professor  Quenstedt  persists  in  his  refusal  to  accept  the  nomenclature  adopted  in 
the  naean  time  by  all  authors  and  corresponding  to  the  actual  state  of  our  knowledge. 
The  want  of  method  and  the  improper  denominations  occasion  much  confusion,  so  that 
the  practical  utility  of  the  work  is  much  diminished,  "  Die  Echiniden  ''  has,  nevertheless, 
a  real  value,  and  has  advanced  science  principally  in  making  known  several  details  of  the 
structure  of  many  species  which  had  not  been  previously  observed,  and  in  many  cases  it 
will  be  consulted  with  advantage.  The  Chalk  of  the  North  of  Germany  has  furnished  to 
M.  Schliiter  (48)  many  new^  species  which  he  has  described  and  figured.  Subsequently 
he  indicated  some  others,  but  only  gave  short  diagnoses  of  them  (49).  Besides, 
many  of  the  Cretaceous  species  from  the  same  region  have  been  well  figured  and 
described  by  Schlcenbach  (50)  ;  and  M.  Dames  has  given  a  description  of  the  Jurassic 
species  collected  in  the  North-west  of  Germany.  The  Echinides  of  the  Upper  Creta- 
.ceous  strata  of  the  Valley   of   the  Elbe   have  been  described   and   figured   by    Prof. 


viii  BRITISH  FOSSIL  ECHINODERMATA. 

Geinitz  (52)  ;  and  M.  Schafliautl  has  given  figures  of  the  Tertiary  species  from  Kres- 
senbertT,  but  in  general  they  have  not  been  determined  in  a  correct  manner.  It  is 
important  moreover  to  cite  the  new  'Handbuch  der  Palseontologie '  by  Prof.  Zittel  (54), 
and  especially  the  well-written  chapter  treating  of  Echinoderms. 

For  the  Empire  of  Austria  I  have  equally  many  Echinologic  works  to  mention.  M. 
Cotteau  (55)  has  made  known  the  Echinides  of  Stramberg,  derived  from  the  strata  about 
which  so  much  controversy  has  taken  place.  M.  Laube  has  decribed  those  from  the 
Bathonian  stage  at  Balin  (56),  and  those  from  the  Upper  Tertiaries  of  Austro-Hungary ; 
and  he  has  discovered  in  the  Eocene  of  the  Mattsee  (5S)  a  new  genus,  the  Oolasfer 
bordering  on  \Anancliytes.  The  ]\Iiocene  strata  of  Ottnang  have  furnished  to  Herr  E.. 
Hoerness  (59)  some  species  ;  and  from  those  of  the  environs  of  Felmenes  some  others 
have  been  noted  by  Herr  Loczy  (60),  amongst  others  a  new  and  interesting  EcJdno- 
cardium. 

The  Urchins  from  the  Eocene  deposits  of  Hungary  and  Transylvania  have  been 
studied  by  Herr  Pavay  (61),  who  had  undertaken  a  general  Monograph  on  the  Echinides 
of  Hungary  (62),  of  which  his  premature  death  only  permitted  him  to  give  a  first  part  to 
the  world. 

The  Cretaceous  strata,  but  especially  the  Tertiary  beds,  of  Istria  and  of  Friuli  (64) 
have  furnished  many  Echinides  to  M.  Taramelli.  His  summary  descriptions  have  been 
completed  by  M.  Bittner  (65),  who  has  also  enriched  the  Tertiary  fauna  of  Istro-Dalmatia 
with  new  and  interesting  species. 

The  Tertiary  strata  of  a  region  bordering  upon  Lombardy  have  been  for  a  long  time 
celebrated  for  their  richness  in  Echinides,  but  a  monographic  study  has  not  yet  been 
made  of  them.  Herr  Schauroth  (66),  in  his  Catalogue  of  the  Museum  of  Coburg,  has 
made  known  in  a  very  imperfect  manner  some  new  species.  Herr  Laube  (67)  has 
much  augmented  the  number  of  forms,  and  grouping  the  whole  of  the  known 
species,  has  endeavoured  to  establish  a  parallelism  amongst  the  beds  in  which  they 
are  found.  Herr  Dames  (68),  following  up  these  observations  in  a  very  extended 
memoir,  has  revised  certain  of  Herr  Laube's  species,  added  new  ones  to  the  list,  and 
established  two  new  interesting  groups : — the  genus  llarionia,  which  approaches 
Pygorhynchis,  but  possesses  a  pentagonal  periostome ;  afterwards  the  curious  genus 
Ovidypem,  which  approaches  very  near  to  Conodypeus,  and  like  it,  was  provided  with  a 
masticatory  apparatus.  It  behoves  us  still  to  cite  a  fossil  species  of  the  genus  Palao- 
pneustes  recently  discovered  in  the  Seas  of  the  Antilles.  The  Tertiary  beds  of  the 
Vicentin  seem  to  be  almost  inexhaustible,  for  Herr  Bittner  (65),  following  up  the  pre- 
cited  memoir  with  another,  has  been  able  to  add  many  more  species,  among  which  he 
has  discovered  several  new  forms  that  were  unknown  to  his  predecessors. 

The  Miocene  Mollusca  of  Italy  have  yielded  to  M.  Manzoni  (69,  70)  many  interesting 
Echinides  ;  and  in  the  Middle  Miocene  he  has  collected  a  large  and  curious  species  of 
SpatangldcE    (71,   72).     M.  Gemellaro  (73)  has  described  some  species  from  the  Upper 


A   RETROSPECT.  ix 

■Sequanian  of  Sicily ;  and  the  Abbe  Stoppani  (74)  has  described  some  species  from  the 
Lower  Lias  of  Lombardy. 

Regarding  the  Echinides  of  Spain  I  have  only  a  few  remarks  to  make.  There  are 
two  works  by  M.  Cotteau,  one  very  short,  relative  to  some  new  Echinides  collected  in 
Spain  by  M.  de  Verneuil  (75),  and  the  other  being  a  contribution  to  a  memoir  of  M. 
Barrois  upon  tbe  Cretaceous  strata  of  the  Province  of  Oviedo,  giving  a  description  of 
some  new  Echinides  from  the  Urgonian  (76). 

The  Echiiiitic  fauna  from  the  Miocene  beds  of  the  Island  of  Malta,  which  is  very  rich 
in  fossil  Urchins  in  a  fine  state  of  preservation,  had  been  previously  studied  and  reported 
upon  by  Dr.  Wright  (77).  These  fossils  were  subsequently  the  subject  of  a  second 
raemoii',  in  which  are  additional  notes,  and  the  description  and  figures  of  some  new 
species.  In  the  Island  of  Melos  a  very  interesting  little  Echinitic  fauna  has  been 
found,  apparently  of  Pliocene  age,  and  in  which  Herr  Dames  has  discovered  a  Cidaris, 
very  different  from  those  which  now  live  in  the  Mediterranean  (78). 

Before  terminating  my  remarks  relating  to  Europe  I  have  still  to  mention  a  little 
work  which  I  have  made  on  the  Tertiary  and  Cretaceous  Echinides  brought  from  the 
Crimea,  by  M.  Ernest  Favre  (79). 

Crossing  now  the  Mediterranean  to  pass  into  Africa  we  arrive  in  Algeria,  which 
appears  to  be  the  promised  land  to  the  Echinologist,  for  in  almost  all  the  geological 
formations  of  this  region  the  Echinides  abound  in  a  surprising  manner.  M.  Coquand 
(80),  in  his  '  Palasontology  of  the  Province  of  Constantine,'  first  made  known  a  great 
number  of  species.  Afterwards  came  the  large  and  beautiful  publication  of  MM.  Cotteau, 
Peron,  and  Gauthier  (81),  which,  commencing  with  the  Jurassic  strata,  undertakes  to 
describe  all  the  Eossil  Echinides  of  Algiers ;  this  work  has  now  reached  the  Senonian 
stage  of  the  Cretaceous  deposits.  Among  the  numerous  species  which  these  rocks 
have  yielded,  the  number  of  those  appertaining  to  the  genus  Hemiaster  is  truly  extra- 
ordinary. In  a  recent  work  by  M.  Coquand  (82),  a  great  number  of  additional  species 
of  the  same  genus  are  described,  but  unfortunately  not  figured,  hence  it  is  impossible 
to  give  an  exact  account  of  the  value  of  their  characters. 

I  am  of  opinion  that  a  general  revision  of  the  species  woidd  result  in  diminishing  the 
number,  for  I  cannot  but  suspect  that  sufficient  allowance  has  not  been  made  for  sexual 
differences,  which  are  important,  and  which  have  been  studied  in  Hemiaster  cavernosus 
living  in  the  Seas  of  Kergueleu,  by  Sir  Wyville  Thomson  ('  Challenger,  Atlantic,'  vol.  ii, 
p.  229),  and  by  Dr.  Theoph.  Studer  ("  Ueber  Geschlechts  Dimorphismus  bei  Echino- 
dermen,"  'Zool.  Anzeiger,'  Nos.  67  and  68,  1880).  The  beds  in  the  North  of  Africa 
are  certainly  far  from  being  exhausted,  and  the  Tertiary  strata  yet  unexplored  doubtless 
contain  many  Echinides  which  by-and-by  will  become  known.  Mr.  Etheridge  has 
described  a  new  Scutelloid  genus  obtained  from  the  Miocene  of  Morocco  (83),  the  genus 
Botuloidea.  The  Tertiary  deposits  of  Egypt  contain  numerous  species  of  Echinides,  of 
which  some  only  have  been  described,  and  for  the  most  part  very  imperfectly ;  they  have 


X  BRITISH   FOSSIL   ECHINODERMATA. 

been  studied  more  completely  of  late  years.  Prof.  Fraas  has  given  an  account  of 
many  Nummulitic  species  (84),  and  has  discovered  the  large  Clypeaster  of  the  Pyramids 
{Clypeaster  jEgyptiacus,^x\^'C),  from  a  Miocene  rock.  I  have  since  published  a  '  Mono- 
graph of  the  Nummulitic  Echinides  of  Egypt '  (85),  in  which  forty-four  species  are  figured 
and  described,  and  in  another  Monograph  (86)  the  Eocene  Echinides  of  Egypt  and  of 
Lybia,  brought  by  Professor  Zittel  from  his  voyage  of  discovery  with  Dr.  Rohlfs, 
the  new  species  are  added  by  me  to  that  interesting  Echinitic  fauna.  I  may  remark 
en  passant  that  I  have  given  in  these  monogi'aphs  figures  of  the  masticating  apparatus  of 
Conoclypeiis  conoidens  which  Dr.  Zittel  had  already  discovered.  This  genus  ought, 
therefore,  to  be  removed  from  the  family  of  the  Cassidulid^Ej  in  which  it  has  hitherto 
been  classed. 

Our  knowledge  of  the  fossil  Echinides  of  Asia  is  not  yet  very  extensive.  Since 
the  '  Monograph  on  the  Nummulitic  Beds  of  India,'  by  MM.  d'Archiac  and  J.  Haime, 
the  only  extended  memoir  which  has  been  published  on  the  subject,  to  my  know- 
ledge at  least,  is  that  of  M.  Stolitzka  (87),  on  the  '  Echinoderms  of  the  Cretaceous 
Formations  of  India,'  in  which  thirty-eight  species  are  figured  and  described.  Some 
isolated  documents  may  still  be  noticed.  Prof.  Duncan  has  enumerated  eleven  Creta- 
ceous species  collected  in  the  South-east  of  Arabia,  and  at  Bagh  on  the  Nerbudda 
(88).  He  has  likewise  given  indications  of  the  Cretaceous  Echinides  of  Sinai  (89). 
M.  Cotteau,  in  a  notice  on  the  Echinides  collected  in  Syria  by  M.  L.  Lartet,  has 
described  some  new  species.  Prof.  Fraas  (91),  in  his  recent  travels  in  Lebanon,  has 
satisfactorily  proved  that  the  spines  so  long  known  under  the  name  of  Cidaris  c/landifera, 
and  believed  to  be  identical  with  those  from  the  Sequanian  stage  are,  on  the  contrary, 
distinct,  and  are  found  in  Cenomanian  beds.  M.  Fuchs,  lastly,  has  made  known  some 
Echinides  from  the  Miocene  beds  of  Persia  (92). 

In  the  Island  of  Borneo  Nummulitic  beds  are  found  containing  Echinides,  of  which 
M.  Fritsch  has  described  some,  establishing  the  genus  Verheekia,  still  very  imperfectly 
characterised  (93). 

Thanks  to  Professor  Zittel  we  know  some  Echinides  from  the  Tertiary  strata  of  New 
Zealand  (94). 

Many  recent  works,  have  had  for  their  object  the  Echinides  from  the  Tertiary  strata 
of  Australia ;  whence  new  species  have  been  described  by  M.  Laube  (95),  Mr.  Etheridge 
(96),  and  Prof.  Duncan  (97),  who  has  given  a  list  of  the  species  from  the  Tertiary 
strata  of  Australia  actually  known.  They  are  to  the  number  of  twenty-four,  and 
embrace  two  new  genera,  Paradoxechinus,  Laube,  and  Meyalaster,  Duncan. 

It  now  remains  for  us  to  cross  the  Pacific  to  California,  where  we  shall  have  to 
remark  upon  some  very  curious  Miocene  and  Pliocene  species  of  Echinides,  discovered 
by  Mr.  Remond  (98),  and  figured  anew  by  Dr.  Gabb  (99).  Some  new  species  are  still 
to  be  indicated  from  the  Eocene  of  South  Carolina,  by  M.  Conrad.  Beyond  this  I  have 
only  been  able   to  discover  a  few  isolated  notices  upon  the   Secondary  and  Tertiary 


A   RETROSPECT.  xi 

Ecliiiiides  of  the  United  States  in  the  works  published  during  tlie  last  twenty  years.  Oa 
the  other  hand,  assisted  by  the  activity  of  my  learned  friend  M.  Cotteau,  whose  name 
I  have  had  to  mention  in  connection  with  the  Echinitic  faunas  of  almost  every  region, 
the  fossil  Echinides  of  the  Antilles  are  now  very  well  known.  Mr.  Guppy  had  already 
published  nine  new  species  from  the  Tertiary  formations  of  the  Island  of  Anguilla.  M. 
Cotteau  (102)  has  added  as  many  as  twenty-six  Eocene  and  Miocene  forms.  He  has 
made  known  the  magnificent  species  of  the  genus  Asterostoma  (103),  of  which  we  had 
known  only  up  to  the  present  the  single  individual  type,  coming  from  the  Tertiary  strata 
of  the  Island  of  Cuba,  where  it  is  accompanied  with  some  other  species,  which  will 
be  figured  afterwards. 

In  South  America  the  Echinitic  works  within  my  knowledge  are  the  isolated 
descriptions  of  some  new  species.  Philippi  (104)  has  described  some  from  Bolivia; 
Herr  Steinraann  (105)  has  just  added  two  others  ;  and  I  have  described  one  from 
Ecuador  (106). 

To  this  rapid  expose  of  the  progress  of  our  knowledge  of  the  fossil  Echinides 
during  the  last  twenty  years,  it  will  not  be  out  of  place  to  add  a  few  words  on  the 
recent  discoveries  which  have  been  made  among  living  Echinides  in  the  existing  seas. 
It  does  not,  however,  appear  necessary  to  enter  into  much  detail  or  to  do  more  than 
mention  the  published  works.  The  magnificent  and  excellent  work  of  Alexander 
Agassiz  (107),  'Revision  of  the  Echini,'  published  between  1872  and  1874,  faithfully 
resumes  all  the  works  anterior  to  it,  and,  so  to  speak,  fixes  our  ideas  upon  the  species  of 
Echinides  known  up  to  this  time  in  our  seas.  It  will  always  serve  as  a  point  de  depart 
for  all  future  works.  The  number  of  distinct  species  which  are  there  found  estab- 
lished and  described  amounts  to  206.  Since  then  the  number  has  been  considerably 
augmented,  but  always  and  almost  solely  by  the  recent  Expeditions  undertaken  for  the 
exploration  of  the  bed  of  the  sea,  aided  by  dredges  and  appropriate  machinery  placed  at 
the  command  of  the  explorers.  Most  of  the  new  types  which  have  been  discovered 
belong  to  the  most  extraordinary  forms ;  and  some  of  these  represent  genera  found 
hitherto  only  in  a  fossil  state,  connecting  in  a  very  remarkable  manner  the  existing  fauna 
with  that  of  former  times.  Already  in  the  Dredging  Expedition  of  the  "  Porcupine," 
Wyville  Thomson  had  observed  in  the  living  state  and  made  known  in  a  complete 
manner  t\ie  Asthenoso7na  (109),  those  regular  Urchins  so  curious  with  a  flexible  test  com- 
posed of  imbricated  plates,  reminding  us  of  certain  Palaeozoic  genera  and  belonging  to 
a  family,  the  EchinothuriDvE,  represented  up  to  the  present  time  by  some  fragments 
found  in  the  Upper  Chalk  and  a  single  example  of  a  recent  species  from  an  uncertain 
province.  We  know  actually  that  it  was  one  of  two  species  all  living  in  depths  from 
10  to  2,750  fathoms,  but  principally  in  the  greatest  depths.  The  appearance  of  the  first 
species  oi  Pourtalesia,  dredged  by  Francois  de  Pourtales  in  the  latitude  of  the  Antilles, 
had  astonished  all  the  Echinologists.  Tins  extraordinary  genus,  bordering  on  the 
Holaster  and  almost  on  the  In/ulaster,  approached  more  particularly  the  Urchins  of  the 


xii  BRITISH   FOSSIL   ECHINODERMATA. 

White  Chalk.  We  have  lately  discovered  that  there  are  several  species,  most  of  them 
bizarres  forms ;  and  the  Expedition  of  the  "  Cliallenger  "  has  made  known  many  new 
genera,  which  are  connected  with  it,  so  that  now  this  species,  known  at  first  by  a  single 
example,  has  become  the  2^oint  de  depart,  a  few  years  after  its  discovery,  of  a  family 
which  appears  to  be  truly  limited  to  great  depths.  These  two  examples  will  suffice 
perhaps  to  make  us  appreciate  the  development  of  our  knowledge  of  the  Echinides  of 
the  actual  seas  during  the  last  eight  years. 

I  do  not  intend  to  enlarge  here  upon  the  new  species  and  the  new  genera  which  have 
been  successively  brought  to  light  by  the  dredging  expeditions  of  the  "  Porcupine,"  of 
the  "Easier"  (110),  of  the  "  Josephine,"  of  the  "Blake"  (HI),  of  the  "  Challenger" 
(112).  This  last,  which  perhaps  may  be  considered  the  most  fruitful,  has  brought  to  our 
knowledge  no  less  than  forty-four  new  species  and  sixteen  new  genera.  We  are  able  to 
estimate  roundly  at  300  the  number  of  the  species  which  we  know  in  our  actual 
seas,  and  it  is  not  only  the  discovery  of  new  types  which  we  owe  to  these  expeditions, 
so  rich  in  results  of  all  kinds,  but  numerous  and  valuable  indications  and  informa- 
tion on  the  geographical  distribution  of  species,  and  on  their  vast  bathymetrical  limits, 
which  are  of  the  greatest  utility  in  explaining  certain  facts  relative  to  the  distribution 
of  fossil  species,  a  subject  upon  which,  perhaps,  we  may  have  experienced  embarrassment. 
Now  that  we  know  that  the  Sjxifangus  Basin  is  found  from  the  Hebrides  to  the  Cape  of 
Good  Hope,  that  the  Brissojjsis  lyrifera  and  the  Schizaster fragUis  are  met  with  both  in 
the  seas  of  Norway  and  in  the  south  of  the  Indian  Ocean,  and  that  certain  species  of 
Cidaris  descend  from  the  shore  to  2000  fathoms,  and  that  a  Phormosoma  descends  from 
200  to  2700  fathoms,  many  facts  relating  to  fossil  Echinides  will  perhaps  be  able  to  find 
an  interpretation. 

This  is  not  the  place  to  recapitulate  the  progress  of  the  state  of  our  knowledge  upon 
the  Morphology,  the  Anatomy,  and  the  Embryogeny  of  the  Echinides  ;  moreover,  I  am 
not  competent  to  imdertake  the  work. 

I  desire  only  to  mention  a  remarkable  w^ork  by  M.  Loven  (113),  '  fitudes 
sur  les  Echinides,'  accompanied  by  fifty-three  excellent  plates  which  contain  very 
curious  and  most  interesting  researches  on  the  structure  of  the  solid  skeleton  of  Urchins, 
and  on  the  different  points  in  their  organisation.  This  useful  work  ought  to  be  studied 
by  all  those  who  wish  to  make  the  Echinides  the  object  of  serious  research. 

My  task  is  now  brought  to  a  termination.  I  hope  that  those  who,  in  the  next 
twenty  years,  undertake  a  similar  work  will  be  able  to  register  as  many  new  facts,  as 
many  new  discoveries,  and  as  much  progress  of  all  kinds  in  the  study  of  this  very 
interesting  group  of  animals,  of  which  T  have  endeavoured  to  give  a  resume  in  the  fol- 
lowing summary  Table,  which  is  probably  less  complete  than  I  wished  it  to  be. 


A   RETROSPECT.  xiii 

Appendix  containing  a  List  of  the  Works  referred  to  in  the  Text.     See 

Page  v. 

1.  Walter  Keeping,  1878.     On  Pelanechinus  (Quart.  Journ.  Geol.  Soc,  vol.  xxxiv), 

2.  Cotteau.     Paleoiitologie  frangaise  (llchinides,  T.  9,  Terrain  cretace ;  T.  9  et  10, 

Terrain  jurassique). 

3.  Ecliinides  du  Departement  de  la  Sarthe,  1855 — 69. 

4.  Cotteau,    1857,   1878.     Etudes  sur  les  fichinides  (Fossiles  du  Dep.  de  PYonne, 

T.  2,  Terrain  cretace). 

5.  Cotteau,  1858 — 80.      Echinides  nouveaux   ou  peu  connus,  le   Serie  (Extrait  de 

Revue  et  Magasin  de  Zoologie). 

6.  Cotteau,  1863.      Note  sur  les  £clunides    nummulitiques  de  Biarritz   (Bull.  Soc. 

Geol.  de  France,  2e  Serie,  T.  21). 

7.  Cotteau,  1865.     Notes  sur  les  Oursins  cretaces  des  Martigues  (Bull.  Soc.  Geol.  de 

France,  2e  Serie,  T.  21). 

8.  Cotteau,  1863.     Ecliinides  fossiles  des  Pyrenees  (Extrait  du  Congres  Scientifique 

de  France,  28e  Session,  T.  3). 

9.  Cotteau,  1865.     Catalogue  raisonne  des  Echinides  fossiles    du    Dep.   de  I'Aube 

(Extrait  du  Congres  Scientifique  de  France,  31e  Session). 

10.  Cotteau,  1871,  in  Dumortier.     Sur  quelques  giseraents  de  I'Oxfordien  inferieur  de 

I'Ardeclie,  Description  du  Echinides. 

11.  Cotteau,  1869.     Descr.  de  quelques  Echinides  Tertiaires  des  environs  de  Bordeaux 

(Actes  de  la  Soc.  Linneenne  de  Bordeaux,  T.  27). 

12.  Cotteau,  1877.     Descr.  des  Echinides  de  la  Colonic  du  Garumnien  de  la  Haute 

Garonne  (Annales  des  Sciences  Geologiques,  T.  9). 

13.  Cotteau,  1877.     Description  des  Echinides  Tertiaires  de  la  Corse,  in  Descr.  de  la 

Faune  des  Terrains  Tertiaires  Moyens  de  la  Corse,  par  A.  Locard. 

14.  Cotteau,  1877.     Catalogue  des  Echinides  jurassiques  de  Normandie  (avec  2  plan- 

ches), Memoires  de  la  Soc.  geologique  de  Normandie. 

15.  Cotteau,  1873.     Sur  le  genre  Tetracidaris  (Bull.  Soc.  Geol.  de  France,  3e  Serie, 

T.  1). 

16.  S^MANN  et  DoLLFUSs,  1861.     Etudes  critiques  sur  les  Echinodermes  fossiles  du 

Coral-rag  de  Trouville  (Bull.  Soc.  Geol.  de  France,  2e  Serie,  T.  19). 

17.  Dumortier,  1864-1872.     Etudes  paleontologiques  sur  les  depots  jurassiques  de 

bassin  du  Rhone. 

18.  TouRNOUER,   1870.      Recensement  des  Echinodermes   du  Calcaire  a  Asteries    du 

S.-O.  de  la  France  (Actes  de  la  Soc.  Linneenne  de  Bordeaux,  T.  27). 

19.  Caffin,  1807.     Echinides  des  environs  d'Evreux  (Bulletin  de  la  Societe  des  Amis 

des  Sciences  Naturelles  de  Rouen). 

20.  BucAiLLE,  1872.     Echinides  fossiles  du  Dep.  de  la  Seine  inferieure. 


xiv  BRITISH   rOSSIL   ECHINODERMATA. 

21.  Hebert,  ]S65.     Etude   d'un  groupe  d'Hemiaster  (Bull.   Soc.  Geolog.   de  France, 

2e  Serie,  T.  22). 

22.  Hebert,  1875.     Descr.  de  deux  Hemipneustes  de  la  Craie  sup.  des  Pyrenees  (Bull. 

Soc.  Geol.  de  France,  3e  Serie,  T.  3). 

23.  Satjvage,    1872.     Note  sur  quelques  Echinoderiues  des  etages  superienrs  format. 

Jurass.  de  Boulogne-sur-Mer  (Bulletin.  Soc.  geol.  de  France,  3e  Serie,  T.  1). 

24.  Arnaud,  1877.     Etude  sur  le  genre  Cyphosoma  dans  la  Craie  du  Sud-Ouest  (Actes 

de  la  Societe  Linndenne  de  Bordeaux,  T.  31). 

25.  Desmoulins.     Etudes  sur  les  Echinides. 

26.  P.  DE  LoRioL,  in  Pictet,  1867.     Faune  Terebr.  diphyoides  de  Berrias;  Melanges 

Pal.,  2  serie. 

27.  P.  DE  LoRioL,  in  Pictet,  1868.     Etude  provisoire  des  Fossiles  de  la   Porte  de 

France,  d'Aizy,  et  de  Lemenc ;  Melanges  Pal.,  iv. 

28.  P.   DE  LoRioL  et    G.  Cotteau,   1868.     Monographic    de    I'etage  Portlandien  de 

I'Yonne  (Bulletin  Soc.  Sc.  Hist,  et  Nat.  de  I'Yonne,  2e  serie,  T.  1. 

29.  P.  DE  LoRiOL  et  Ed.  Pellatt,  1866.     Monogr.  de  I'etage  Portlandien  de  Boulogne- 

sur-Mer  (Mem.  Soc.  de  Physique  et  d'Hist.  Nat.  de  Geneve,  T.  19),  et  Monogr. 
des  Etages  superienrs  de  la  formation  Jurassique  de  Boulogne-sur-Mer  (Meui. 
Soc.  Phys.  et  Hist.  Nat.  de  Geneve,  T.  23  et  24). 

30.  P.  DE  LoRiOL,  E.  RoYER,  et  H.  Tombeck,  1872.     Monogr.  pal.  et  geol.  des  etages 

sup.  de  la  formation  Jurassique  de  la  Haute  Marne  (Memoires  de  la  Soc. 
Linneeune  de  Normandie,  vol.  xvi). 

31.  DujARDiN  et  Hupi,  1862.     Histoire  Naturelle  des  Zoophytes  Echinodermes. 

32.  Etallon,  1860.     Rayonnes  du  jurassique  superieur  de  Montbeliard. 

33.  Etallon,   1864.     Paleontologie    du    Jura   Graylois  (Mem.    Soc.    d'Emulation    du 

Doubs,  3e  serie,  vol.  viii). 

34.  Etallon,  ]  860.     Etudes  Paleontologiques  sur  le  Corallien  du  Haut  Jura. 

35.  Thurmann  et  Etallon,  1862.     Lethsea  Bruntutana  (Memoires  de  la  Societe  Helv. 

des  Sc.  Naturelles). 

36.  OosTER,  1865.     Synopsis  des  Echinodermes  fossiles  des  Alpes  Suisses, 

37.  OosTER,  1869-72.     Protozoa  Helvetica. 

38.  P.  DE  Loriol,  1863.     Descr.  des  animaux  invert,  foss.  du  necomien  du  Saleve. 

39.  P.  DE  LoRioL,  1866.     Descr.  des  foss.  coralliens,  Valangiens,  et  Urgoniens  du  Saleve, 

in  A.  Favre,  Recherches  geologiques  sur  la  Savoie,  &c. 

40.  P.  DE  LoRioL,  1868.     Monogr.  des  conches  de  I'etage  Valangien  d'Arzier  (Materiaux 

par  la  Paleontolog.  Suisse,  publics  par  F.  J.  Pictet). 

41.  P.  DE  LoRioL,  1869,  in  P.  de  Loriol  et  V.  Gillieron.     Monogr.  de  I'etage  Urgo- 

nien  du  Landeron  (Mem.  de  la  Soc.  Helv.  des  Sc.  naturelles). 
42a.  E.  Desor  et  P.  de  Loriol,  1868  and  1872.     Echinologie  Helvetique,  lere  partie, 
Echinides  jurassiques. 


A   RETROSPECT.  xv 

42(5.  P.  DE  LoRiOL,  1873.  Echiiiologie  Helvetique,  2e  partie,  Echinides  cretaces 
(Materiaux  pour  la  Paleontologie  Suisse,  publies  par  F.  J.  Fictet). 

4.2c.  P.  DE  LoRioL,  1875-76.  Echinologie  Helvetique,  3e  partie.  Echinides  tertiaires 
(Memoires  de  la  Soc.  paleont.  Suisse,  vol.  ii  et  iii). 

43.  G.  CoTTEAU,   1875.     Note  sur  les  Echinides  cretaces  du  Hainaut  (Bull.  Soc.  geol. 

de  France,  3e  Serie,  T.  II). 

44.  G.  CoTTEAU,  1878.     Descr.  des  Echinides  du  Calcaire  grossier  de  Mons.  (Memoires 

de  I'Acad.  de  Belgique,  T.  42). 

45.  G.  CoTTBAU,  1880.     Descr.  des  Echinides  tertiaires   de  la  Belgique  (Memoires  de 

I'Academie  de  Bruxelles,  T.  43). 

46.  G.  CoTTEAU,  1870.     Descr.  de  quelques  especes  d'Echinides  de  Suede  (Bibl.  de 

I'ecole  des  Hautes  Etudes,  Sc.  naturelles.  T.  2). 

47.  QuENSTEDT,  1875.     Die  Echiniden. 

48.  Cl.  ScHLtJTER,    1869.     Fossile  Echinodermen  des  nordlichen  Deutschlands  (Verh. 

der  nat.  Ver.  der  Preuss.  Rheinlandes,  vol.  xxvi). 

49.  Cl.  ScHLtJTER,    1870.     Diagnosen  neuer  fossilen  Echinodermen    (Verh.    der   nat. 

Verh.  Preuss.  Rheinlands,  vol.  x.xvii). 

50.  ScHLOENBACH,  1869.     Bcitrag  zur  Alters  Bestimmnung  der  Grunsandes  v.  Roth- 

enfelde  (Leonh.  und  Geinitz,  Neues  Journal  fiir  Miner.,  &c.,  1869). 

51.  Dames,  1872.     Die  Echiniden  der  nordwest.  deutschen  Jura  Bildungen  (Zeitsch.  der 

Deutschen.  Geol.  Gesell.,  vol.  xxiv). 

52.  Geinitz.     Das  Elbthalgebirge  in  Sachsen  (Palseontographica). 

53.  ScHAFHAUTL,  1863.     Siid-Bayerns  Lethsea  geognostica,  Kressenberg. 

54.  ZiTTEL,  1879.     Handbuch  der  Palaontologie,  Vol.  I,  3e  Livr. 

55.  CoTTEAU,  in  Zittel,    1870.     Fauna  der  aelteren  Cephalopoden  filhrenden  Tithon 

Bildungen. 

56.  Laube,  1867.     Die  Echinodermen  des  braunen  Jura  von  Balin  (Denkschr.  der  K. 

K.  Akad.  der  Wissenschaft.,  Wien,  vol.  xxvii). 

57.  Laube,  1871.     Die  Echinoiden  der  Oesterreich-Ungarischen  oberen  Tertiar  Ablager- 

ungen  (Abhandlungen  der  K.  K.  geolog.  Reichsanstalt,  vol.  v). 

58.  Laube,  18G9.     Ueber  Oolaster,  neues  Echin.  Gesch.  von  der  Eocenen  Schichten  in 

Mattsee  in  Oesterreich   (Leonhard  und  Geinitz,   Neues  Jahrb.  fiir  Mineralogie, 
1869,  f.  454). 

59.  R.  IToRNESs,  1875.      Die  Fauna  des  Schliers  in  Ottnang  (Jahrbuch  der  K.  K.  geoL 

Reichtanstalt,  vol.  xxv). 

60.  LoczY,  1877.     Echinoiden  aus  den  neog.  Ablag.   des  weissen  Korosthaler  (Terme 

szetrajzi  Tuzetck,  1st  Heft). 

61.  Dr.  Al.  DE  Pavay,  1873.     Geologic  Klausenburgs  und  seiner  Unigebung  (Mitth. 

aus  den  Jahrbuch.  der  Konigl.  Ung. 'Geolog.  Anstalt,  vol.  i). 


xvi  BRITISH   FOSSIL   ECHINODERMATA. 

62.  Dr.  Al.  de  Pa  vat,  1874.     Die  fossilen  Seeigel  des  Ofner  Mergels  (Mitth.  aus  den 

Jahrbuch.  der  Kon.  Ung.  geol.  Anstalt,  vol.  ii). 

63.  Taramelli,  1874.     Nota  sopre  alciini  Ecliinidi  del  Istria  (Atti  del  Reale  Istituto 

Venete,  Serie  iv,  Tome  3). 

64.  Taramelli,  1868.     Note  sopra  alcuni  Echiiiidi  cretacei  e  teiziarii  del  Fiiuli  (Atti 

del  Reale  1st.  Veneto,  Serie  3,  vol.  xiv). 

65.  BiTTNER,  1880.     Beitrage  zur  Kenntniss  Alttiarer  Ecliiniden  fauneu  der  Siidalpen 

(Beitrage  zur  Palaontologie  von  Oesterreich.  Ungarn.,  vol.  i). 

66.  ScHAUROTH,  1865.     Verzeichniss  der  Versteinerungen  in  Herzogl.  Natur.  Cabinet 

zur  Coburg. 

67.  Laube,  1868.     Ein  Beitrag  zur  Kenntniss  der  Echinodermen  des  Vicentinischen 

Tertiar-Gebietes  (Denkschriften  der  Wiener  Akademie  der  Wiss.,  vol.  xxix). 

68.  Dames,  1877.     Die  Echiniden  der  Vicentinischen  and  Veronesischen  Tertiaerabla- 

gerungen  (Pal^ontographica,  vol.  xxv). 

69.  Manzoni,  1873.     II  Monte  Titano. 

70.  Manzoni  et  Mazzetti,  1878.     Echinodermi  nuovi  delle  Molassa  miocenica  di  Mon- 

tese  (Atti  della  Soc.  Toscana  di  So.  Nat.). 

71.  Manzoni,  1878.     Gli   Echinodermi  fossili  dello  Schlier  delle  colline    di    Bologna 

(Denkschriften  der  Wiener  Akademie  der  Wiss.,  vol.  xxxix). 

72.  Manzoni,  1880.     Echinodermi  fossili  della  Molassa  Serpentinosa  (Denkschriften 

der  Wiener  Akademie  der  Wiss.,  vol.  xlii). 

73.  Gemellaro,  1871.     Studi  paleont.  sulla  Fauna  del  Calc.  a  Ter.  janitor  del  nord  di 

Sicilia,  iii. 

74.  Stoppani,  1863.     Paleontologie  Lombarde,  3e  serie.  Infra-lias  de  Lombardie. 

75.  CoTTEAU,  1860.     Note  sur  quelques  Echinides  recueillis  en    Espagne  par  M.   de 

Verneuil  (Bulletin  Soc.  Geol.  de  France,  2e  serie.  Tome  17). 

76.  CoTTEAU,  1879.     Notice  sur  les  Echinides  urgoniens  recueillis  par  M,  Barrois  dans 

la  Province  d'Oviedo  (Annales  des  Sc.  geologiques,  x). 

77.  Dr.  T.  Wright,  1864.     On  the  Fossil  Echinidge  of  Malta   (Quarterly  Joimial  of 

the  Geol.  Soc.  of  London,  vol.  xx). 

78.  Dames,    1877.     Echiniden    fauna   von    der   Insel   Melos.  (Sitzungs-Berichte    des 

Gesell.  Naturforscher  zu  Berlin,  1877). 

79.  P.  DE  Loriol,  1877.     In  the  Etude  stratigraphique  de  la  Partie  S.  0.  de  la  Crimee, 

par  Ernest  Favre. 

80.  CocjUAND,  1862.     Geologic  et  Paleontologie  de  la  Province  de  Constantine. 

81.  CoTTEAU.      Peron    et    Gauthier,    1873-1881     (Echinides    fossiles    de    I'Algerie, 

7  fascicules). 

82.  CoQCAND,  1880.     Etudes  supplementaires  sur  la  Paleontologie  Algerienne. 

83.  Etheridge,  1872.     Description  of  a  new  genus  of  fossil  Scutelloid  Echinoderm 

from  Saffe,  Morocco  (Quart.  Journ.  Geol.  Soc.  of  London,  vol.  xxviii). 


A   RETROSPECT.  xvii 

84.  Eraas,  1867.     Aus  dera  Orient.  (Wiirttemb.  Naturn.  Jalireshefte,  1867). 

85.  P.   DE  LoRiOL,  1880.     Monographie   des    Echinides  nummulitiques  de  I'Egypte 

(Mem.  de  la  Soc.  de  Pliys.  et  d'liist.  nat.  de  Geneve,  T.  27). 

86.  P.  DE  LoRiOL,  1881.     Beschreibiing  deraus  seiner  Reise  niit  der  Rolilfsclier  Expe- 

dition ;  von  Herrn  Prof.  Zittel  mitgebrachten  Ecliiniden  (Pateontographica). 

87.  Stolitzka,  1873.     Monograph  of  the  Echinodennata  of  the  Cretaceous  Deposits  in 

Sonth  India  (Memoirs  of  the  Geological  Survey  of  India). 

88.  Duncan,  1865.     Descr.  of  the  Echinodermata  from  the  Strata  on  the  S.  E.  Coast  of 

Arabia,  and  Bagh  on  the  Nerbudda  (Quart.  Journ.  Geol.  Soc.  London,  vol.  xxi. 

89.  Duncan,  1867.     Descr.  of  some  Echinoderms  from  the  Cretaceous  Rocks  of  Sinai 

(Quart.  Journ.  Geol.  Soc.  London,  vol.  xxiii). 

90.  Cotteau,  1869.     Notice  sur  les  Echinides  recueillis  par  M.  Lartet  en  Syrie  (Bull. 

Soc.  geol.  de  France,  2e  serie,  T.  26). 

91.  Eraas,  1878.     Aus  dem  Orient,  ii  (Geolog.  Beob.  am  Libanon). 

92.  Th.  Fuchs,  1880.     Ueber  einige  Tertiare  Echiniden  aus  Persia  (Sitzungsber.  der 

Wiener  Akademie  der  Wiss.,  vol.  Ixxxi). 

93.  V".    Fritsch,    1877.      Die    Echiniden    der    nummulitenbildnngen    von     Borneo 

(Palseontographica) . 

94.  ZiTTEL,  1869.     Fossile  Mollusken  xmd  Echinodermen  aus  Neu-Zeeland  (Novara- 

Expedition,  vol.  i). 

95.  Laube,  1869.     Ueber  einige    fossile   Echiniden   von    den  Murray^  Cliffs  in  Sud 

Australien  (Sitzungsberichte  der  Wiener  Akad.  der  Wiss.,  vol.  lix). 
96«.  Etheridge,  1875.     On  Australian  Tertiary  Echinoderms  (Quart.  Journ.    Geol. 

Soc,  vol.  xxxi). 
965.  Etheridge,  1875.     Descr.  of  a  New  Species  of  the  genera  Hemipatagus  from  the 

Tertiary   Rocks  of  Victoria,  Australia   (Quart.    Journ.    Geol.  Soc.    of  London, 

vol.  xxxi). 

97.  Duncan,  1876.      On  the  Echinodermata  of  the  Australian  Cainozoic  Deposits 

(Quart.  Journal.  Geol.  Soc.  London,  vol.  xxxiii.) 

98.  Remond,  1863.     Proceed.  California.  Acad,  for  1863. 

99.  Gabb,  1869.     Geol.  Survey  of  California ;  Palaeontology,  vol.  ii. 

100.  Conrad,    1865.      Catalogue  of  the  Eocene  Echinodermata,   &c.,  of  the  United 

States  (Proceed.  Acad.  Nat.  Sc,  Philadelphia,  2nd  series,  vol.  ix). 

101.  GuppY,   1866.     West-Lidian    Echinoderms  (Quart.   Journ.   Geol.   Soc,   London, 

vol.  xxi). 

102.  Cotteau,  1875.      Description  des    Echinides  Tertiaires  des   Antilles    (Mem.   de 

I'Academie  de  Suede,  vol.  xiii). 

103.  Cotteau,  1871.     Notice  sur  le  genre  Asterostoma  (Mem.  Soc.  Geolog.  de  France, 

2e  Serie,  T.  9). 

104.  Philippi,  1860.     Reise  in  die  Wiiste  Atacama. 


xviii  BRITISH   FOSSIL   ECHINODERMATA. 

105.  Steinmann,   18S1.     Die  Kenntniss  der  Jura  und  Kreideformation  in  Caracoles, 

Bolivia. 

106.  P.  DE  LoRioL,  1876.     Note  sur  quelques  esp.  nouvelles  appartenant  a  la  Classe  de 

Echinodermes  (Mem.  Soc.  de  Phys.  et  d'Hist.  nat.  de  Geneve,  T,  24). 

107.  Alexander  Agassiz,  1872-74.     Revision  of  the  Echini  (Illustrated  Catalogue  of 

the  Museum  of  Compar.  Zoology  at  Harvard  College,  No.  7). 

108.  Wyville  Thomson,  1873.     The  Depths  of  the  Sea, 

109.  Wyville  Thomson,  1874.     On  the  Echinoidea  of  the  "Porcupine"  Deep  Sea 

Dredging  Expedition  (Philos.  Trans,  of  the  Royal  Soc.  of  London,  vol.  clxiv). 

110.  Alexander  Agassiz,  1874.     Zoological  Results  of  the  Hasler  Expedition;  Echini 

(Illustrated  Catalogue  of  the  Museum  of  Compar.  Zoology  at  Harvard  College, 
No.  8). 

111.  Alexander  Agassiz,  1878.     Report  on  the  Results  of  Dredging  ....   by  the 

U.  S.  Coast  Survey  Steamer  "  Blake ; "  Echini  (Bull.  Mas.  of  Compar.  Zool.  at 
Harvard  College,  vol.  v.  No.  9), 
Alexander  Agassiz,  1880.     Idem.,  idem.      (Bull.   Mas.  of  Compar.  Zool.  at 
Harvard  College,  vol.  viii.  No.  2). 

112.  Wyville  Thomson,  1877.     The  Voyage  of  the  "  Challenger;  "  the  Atlantic. 
Alexander  Agassiz,  1879.     Preliminary  Report  on  the   "Challenger;"  Echini 

(Proceed.  Amer.  Acad,  of  Arts  and  Sciences,  vol.  xiv). 

113.  LovEN,  1874.     fitudes  sur  les  Echinoidees  (Kougl.  Svenska  Veteuskapt.  Akade- 

miens  Handlingar,  vol.  xi)." 


THE 


PALJIONTOGRAPHICAL  SOCIETY. 


INSTITUTED    MDCCCXLVII. 


LONDON 


MUCCCLXIT. 


A   MONOGRAPH 


ON    THE 


BRITISH    FOSSIL 


ECHINODERMATA 


FROM 


THE    CRETACEOUS    FORMATIONS. 


BT 


THOMAS    WRIGHT,    M.D.,    F.R.S.  Edin.,    F.G.S., 

COBEESPONDING    MEMBER   OP   THE    HOTAL   SOCIETY   OF   SCIENCES    OF    LIEGE, 
AND   SENIOR  SUEGEON   TO   TUE    CHELTENHAM   HOSPITAL. 


VOLUME  FIRST. 


PART  FIRST. 
ON    THE    CIDARID^. 


LONDON: 

PRINTED  FOR  THE  PAL^ONTOGRAnilCAL  SOCIETY. 

1864. 


J.    E.    ADL4RD,    PRINTKR,    BARTHOLOMEW    CLOSE. 


A   MONOGRAPH 


ON    THE 


CRETACEOUS    ECHINODEKMATA. 


ON  THE  CRETACEOUS  GROUP. 

The  Cretaceous  group,  as  a  whole,  as  developed  in  England,  has  been  so  fully 
described  by  Conybeare  and  Phillips,^  and  its  subdivisions  by  other  authors,^  that  it 
appears  to  be  unnecessary  to  devote  any  great  space  to  this  branch  of  the  subject,  beyond 
an  epitomized  outline  of  the  subdivisions  of  the  Cretaceous  rocks,  with  brief  notes  on  the 
species  of  Ecldnidce  found  therein,  and  the  co-relation  of  these  stages  with  their  equivalent 
zones  of  life  in  the  Cretaceous  systems  of  the  Continent  of  Europe ;  and  as  the  Isle  of 
Wight  exhibits   some  of  the  best  coast-sections  of  the  Cretaceous  rocks  in  the  British 

'  The  '  Outlines  of  the  Geology  of  England  and  Wales '  contains  a  most  able  account  of  this  formation. 

2  Tiie  following,  among  many  others,  may  be  consulted  for  important  information  on  the  Cretaceous 
formation  : — Dr.  Fitton's  various  memoirs  in  the  '  Geol.  Transactions,'  and  '  Quarterly  Journal  of  the  Geol. 
Soc. ;'  Sir  H.  De  La  Beche,  "  On  the  Chalk  and  Greensand  of  Lyme  Regis,"  '  Geol.  Trans.,'  vol.  ii ;  Young 
and  Bird  and  Professor  John  Phillips  on  the  Geology  of  Yorkshire ;  Dr.  Mantell's  works  on  the 
Geology  of  Sussex  ;  Samuel  Woodward's  'Geology  of  Norfolk  ;'  Dixon's  '  Geology  of  Sussex.'  The  various 
memoirs  in  the  '  Quarterly  Journal  of  the  Geol.  Soc'  on  the  Cretaceous  Rocks,  by  Professor  E.  Forbes, 
Messrs.  Lonsdale,  Rose,  Austen,  Cunnington,  Morris,  Weaver,  Rose,  Clarke,  Bunbury,  Bowerbank, 
R.  C.  Taylor,  Ibbetson,  Toulmin  Smith,  D.  Sharpe.  The  Manuals  of  Geology,  by  Sir  H.  De  La  Beche, 
Sir  Charles  Lyell,  and  Professor  Jukes ;  and  the  "  Geology  of  the  Isle  of  Wight,"  by  Mr.  H.  W.  Bristow, 
in  the  '  Memoirs  of  the  Geological  Survey.'  The  reader  will  likewise  find  most  valuable  information 
in  Le  Vicomte  D'Archiac's  '  Histoire  des  Progrcs  de  la  Geologic,'  tom.  iv  and  v,  "  Sur  la  Formation 
Cretac^e ;"  the  memoirs  by  M.  E.  Gueranger,  in  the  '  Bull.  Soc.  Geol.  de  France ;'  M.  Cornuel's 
"  Section  of  the  Environs  of  Vassy  "  ('  Mem.  Soc.  Geol.  de  France,'  t.  iv)  ;  M.  Leymerie's  "  Memoir  on 
the  Department  of  the  Aube"  ('Mem.  Soc.  Geol.  de  France,'  t.  ivand  v)  ;  and  in  the  different  important 
works  by  the  late  M,  Alcide  d'Orbigny. 

1 


2  CRETACEOUS  GROUP. 

Islands,  in  their  stratigraplucal  order  of  superposition,  I  shall  take  these  as  a  type  of  the 
whole,  supplying  any  deficiency  in  the  series  by  examples  afforded  by  other  localities. 

THE  LOWER  GREENSAND. 

The  Lower  Greensaiid,  occupies  an  extensive  tract  in  the  southern  part  of  the  Isle  of 
Wight,  where  it  attains  a  thickness  of  nearly  900  feet;  this  great  formation  has  been  so 
carefully  examined  and  well  described  by  the  late  Dr.  Eitton,^  in  his  stratigraphical 
account  of  the  section  from  Athertield  to  Rocken  End,  on  the  south-west  coast  of  the 
island,  that  I  must  refer  the  reader  for  full  information  to  that  valuable  memoir  for  further 
details.  Having  worked  several  times  over  all  the  beds  of  that  remarkable  and  most  in- 
structive district,  aud  in  my  excursions  had  the  advantage  of  the  local  knowledge  and 
assistance  of  Dr.  Eitton's  collector  and  guide,"  I  shall  now  merely  attempt  a  generalized 
account  of  this  section,  for  the  purpose  of  pointing  out  the  beds  with  which  we  are  more 
immediately  interested,  in  our  description  of  the  Echiuids  contained  therein. 

The  entire  series  of  the  Lower  Greensand  beds,  809  feet  in  thickness,  rise  in  succes- 
sion from  the  shore  aud  ascend  into  the  cliffs  between  Atherfield  Point  and  Rocken  End, 
towards  which  they  dip  at  an  inclination  of  about  2°. 

The  following  Subdivision  of  the  Atherfield  Section  was  proposed  Jjy  Br.  Fitton,  in 

ascending  order. 

Feet.  Inches. 

I.  Perna  MuUeti  Bed 5  3 

II.  Atherfield  Clay    60  0 

III.  The  Cracker  Rocks 85  0 

IV.  The  Lower  Grypheea  Group 32  0 

V.  Scaphites  Group 50  4 

VI.  Lower  Crioqeras  Group 16  3 

Vil.  Walpeu  Clays  aud  Sands    57  0 

VIII.  Upper  Crioceras  Group  46  2 

IX.  Walpen  aud  Ladder  Sands     42  0 

X.  Upper  Gryphsea  Group  16  0 

XI.  Cliff-End  Sands  20  0 

XII.  Foliated  Clay  and  Sand 25  0 

XIII.  Sands  of  Walpen  and  Black-Gang  Undercliff  97  0 

XIV.  Ferruginous  Sands  of  Black-Gang  Chine 20  6 

XV.  Upper  Clays  and  Sand-Rock , 118  0 

XVI.  Various  Sands  and  Clays   118         4 

808       10 

1  "  A  Stratigraphical  Account  of  the  Section  from  Atherfield  to  Rocken  End,  in  the  South-west  Coast  of 
the  Isle  of  Wight,"   '  Jour,  of  the  Geol.  Soc'  vol.  iii,  p.  289,  1847- 

-  Mr.  Charles  Wheeler,  fisherman,  at  Ventnor,  is  the  person  alluded  to,  he  has  a  most  correct  know- 
ledge of  the  range  and  position  of  all  the  beds,  aud  of  their  fossil  contents,  and  is  a  most  trustworthy 
guide  to  the  Atherfield  Section. 


LOWER  GREENSAND.  3 

I.  The  Ferna  beds,  which  here  form  the  base  of  the  Lower  Greensand,  rest  upon 
Weald  clay ;  the  junction  between  the  lacustrine  series  of  the  latter  with  the  marine 
deposits  of  the  former  exhibit  no  trace  of  disturbance;  a  thin  seam  of  bone-bed,  composed 
of  the  teeth  of  fish  of  lacustrine  species,  attest  a  change  of  conditions  similar  to  that 
observed  in  some  junction-beds  in  other  formations,  as  between  the  Upper  Keuper  and  the 
Lias,  and  the  Upper  Silurian  and  Devonian  series.  This  junction,  which  is  only  sometimes 
visible,  occupies  about  eight  inches  of  vertical  thickness ;  on  one  occasion  I  succeeded 
in  detaching  a  block  of  rock,  about  a  foot  thick,  from  the  beds,  the  lower  half  of 
which  contained  the  lacustrine  shells  of  the  Weald  clay,  whilst  in  the  upper  half  Perna 
Mulleti,  Desh.,  Exo(/yra  sinuata,  Sow.,  and  other  Lower  Greensand  shells,  were  found. 
The  Perna  beds  rise  from  the  base  of  the  cliff,  at  a  point  a  few  yards  to  the  east  of  the 
flag-staff  of  the  coastguard-station ;  they  consist  of  dark-blue  sandy  clay  and  greenish 
sand,  forming  in  parts  a  very  hard  rock,  and  characterized  by  that  remarkable  shell  Perna 
Mulleti,  Desh.,  which  is  not  found  in  any  other  bed  in  the  section.  Nearly  one  hundred 
species  of  marine  shells  are  found  in  the  Perna  beds ;  among  these  Nautilus  Requinianus, 
d'Orb,,  and  Exogyra  sinuata.  Sow.,  appear  for  the  first  time,  of  very  large  size,  and 
Hemipneustes  Fittonii,  Forb.,  among  the  Echinida,  with  the  remains  of  fish  belonging  to 
the  genera  Lamna,  Odontaspis,  Saurocephalxs,  Hyhodus,  &c. 

n.  The  Jtherfleld  Clay  is  of  a  drab  colour,  passing  into  bluish-gray,  and  contains 
flat  nodular  masses.  Ammonites  Deshayesii,  Leyra.,  Pinna  Robinaldina,  d'Orb.,  and  several 
other  species  of  Conchifera,  with  the  bones  of  a  Turtle,  and  the  remains  of  Echinidae,  are 
found  in  this  bed. 

in.  The  Crackers,  so  called  from  the  noise  produced  by  the  waves  dashing  over  the 
ledges  formed  by  these  rocks  on  the  shore,  are  the  most  interesting  fossiliferous  group  of 
the  entire  series,  and  consist  of  alternations  of  sandy  clays  and  clays,  and  two  layers  of 
ferruginous  sandy  nodules.  All  the  clays  resemble  Pullers'  earth,  and  the  sand  between 
the  nodular  concretions  in  the  lower  bed  is  sometimes  indurated  into  an  imperfect  stone. 
The  lower  part  of  this  group  is  a  brown  clay  and  sand,  called  the  Lower  Lobster  bed,  from 
the  number  of  Asfacus  Vectensis,  Bell,  found  therein  ;  the  succeeding  beds  are  sands, 
containing  concretionary  masses  of  sandstone  full  of  beautiful  fossil  shells.  Ammonites 
Deshayesii,  Leym.,  Pholadomya  Martini,  Porb.,  Myacites plicata.  Sow.,  Corbula  striatula. 
Sow.,  and  several  other  Conchifera.  Many  of  the  Myadce  are  found  in  the  upright  position 
they  assumed  during  life.  The  lower  sandstone,  from  a  foot  to  eighteen  inches  in  thick- 
ness, is  almost  entirely  made  up  of  GervUlia  aviculoides.  Sow.,  Triyonia  Dadalcea,  Park., 
Ammonites  Deshayesii,  Leym.,  and  other  shells.  The  upper  layer  of  sandstone  contains 
coniferous  wood  and  a  Teredo,  and  the  upper  clays  are  fossiliferous  throughout.  In  the 
concretionary  nodules  of  the  lower  series  of  this  group  I  have  collected  Pseudodiadema 
Autissodorense,  Cott.,  P.  Ibbetsoni,  Forb.,   and  Hemipneustes  Fittoni,    Porb.,   Avith    the 


4  LOWER  GREENSAND. 

beautiful  winged  shells  BosteUaria  glabra,  Forb.,  E.  reli/sa,  Sow.,  Pterocera  Fittoni, 
Forb.,  and  several  species  of  Cerithia,  as  Cerithium  turriculatitm,  Forb.,  C.  Neocomiense, 
d'Orb.,  and  C.  PMUipsi,  Leym. 

IV.  The  Lower  Gryj)haa  or  Exogyra  Group  has  for  its  base  a  thick  bed  of  ferrugi- 
nous sand,  overlain  by  sand  containing  Perna  alaformis,  Sow.,  and  Terebratula  sella.  Sow., 
in  great  abundance,  in  thin  seams  of  sand.  The  zones  with  Exo(jyra  sinuata,  Sow.,  which 
here  are  very  large,  are  found  in  the  upper  part  of  the  group. 

V.  The  ScaphUes  Group  forms  three  beds ;  the  lowest  is  composed  of  brown  ferru- 
ginous sand,  containing  Exogyra  sinuata,  Sow.,  Terebratula  sella,  Sow.,  Bhytichonclla 
Gibbsiana,  Sow. ;  and  of  the  Echinidse  I  found  Cardiaster  Benstedi,  Forb.,  and  Nmleolites 
Olfersii,  Ag. ;  the  middle  beds,  about  two  feet  in  thickness,  contain  layers  of  nodules 
enclosing  Scaphites  giyas,  Sow.,  and  ScaphUes  Hillsii,  Sow. ;  the  upper  consist  of  thick 
beds  of  greenish  sand,  containing,  in  the  upper  part,  fine  large  specimens  of  Exogyra 
sinuata,  ^ow. 

VI.  The  Loioer  Crioceras  Group  consists  of  ranges  of  large  sandy  nodules,  enclosing 
Crioceras  Bowerbankii,  Sow. ;  the  lowest  range  rises  on  the  west  of  Whale  Chine,  and  is 
succeeded  by  two  other  ranges,  all  three  enclosed  in  sand  about  nine  feet  thick  ;  the 
lowest,  furnishing  the  best  fossils,  passes  the  bottom  of  Whale  Chine,  from  whence  I 
have  obtained  several  large  specimens. 

VII.  The  Walpen  and  Ladder  Sands  and  Clay  extend  from  the  east  of  Walpen  to  half 
way  between  Ladder  and  Whale  Chines,  where  they  are  well  seen ;  the  lower  half  of  this 
group  contains  Ammonites  Martini,  d'Orb.,  and  a  large  Gryphcea ;  the  upper  half, 
which  is  clayey  below  and  sandy  above,  contains  Dentalium,  Myacites  mandibula,  Sow., 
Pinna  Bobinaldina,  d'Orb. 

VIII.  The  Upper  Crioceras  Group  consists  of  sandy  nodules  imbedded  in  sand,  and 
contains  Crioceras  Botuerba^ihii,  Sow.,  Ammonites  Martini,  d'Orb.,  Gervillia  solenoides, 
Defr.,  Terebratula  sella.  Sow.,  and  several  other  shells.  This  group  is  seen  for  some 
distance  along  the  shore  east  of  Walpen  Chine,  which  is  crossed  by  it,  as  are  also  Ladder 
and  Whale  Chines. 

IX.  The  Walpen  and  Ladder  Sands  consist  of  gpcenish  and  gray  sand,  with  a  layer 
of  large  fossiliferous  nodules  at  the  base,  containing  Serpulce,  Thetis,  Gervillia,  Cucullcea, 
Corbula,  and  other  shells,  together  with  an  Urchin  belonging  to  the  genus  Brissus. 

X.  The  Second  Gryphaa  or  Exogyra  Group. — The  lower  part  of  this  group  consists  of 


LOWER  GREENSAND.  5 

sand  and  clay  containing  small  nodules  enclosing  a  Brissus,  Ammonites  Martini,  d'Orb., 
and  detached  valves  of  Exogyra  sinuata ;  above  are  three  or  four  ranges  of  Exoc/yra 
sinuata,  Sow.;  the  parallel  edges  of  these  large  shells,  as  seen  in  the  cliff,  indicate  three  or 
four  continuous  strata,  with  irregular  clusters  between  them.  The  second  or  upper 
Gryphaea  group  appears  at  low  water  at  Shankliu,  where  the  several  ranges  of  Exoyyrcs 
are  seen  rising  beneath  each  other.  Varieties  of  this  shell  appear  to  me  to  charac- 
terize different  beds ;  for  example,  the  specimens  of  Exoyyrce  from  the  Crackers  and 
Lower  Gryphaea  group  present  marked  differences  when  compared  with  shells  of  the 
same  species  from  the  Upper  Gryphtea  group.  A  similar  observation  has  been  made  by 
M.  Cornuel  on  the  Exoyyrce  collected  by  him  near  Vassy,  in  France.  This  geologist 
assured  Dr.  Fitton  "  that  he  could  at  once  assign  each  variety  of  form  to  a  special  place 
in  the  section  of  that  vicinity."  Small  fragments  of  vegetable  remains  {Lonchopferis 
Mantellii,  Brong.)  occur  not  only  in  these  beds,  but  nearly  throughout  the  entire 
formation. 

XL  The  Cliff-End  Sands  consist  of  uniform  sand  about  fourteen  feet  thick,  with  a 
subordinate  bed  of  fossiliferous  clay  containing  Triyonia  Dcedalcea,  Park.,  in  the  lower  part, 
and  plant-like  pyritiferous  concretions  in  sand  and  clay  in  the  upper  part. 

XIL  Foliated  Clay  and  Sand. — Consist  of  alternations  of  dark- blue  clay  and  greenish, 
translucent,  siliceous  sand,  containing  nodules  of  pyrites  and  large  irregular  masses  of 
coarse  sandstone.  These  beds  are  well  seen  in  Walpen  and  Black-Gang  Chines,  but  no 
fossils  have  hitherto  been  found  in  them. 

XIIL  Sands  of  WaljK'n  and  Black-Gany  Under  cliff. — This  group  commences  with 
a  bed,  about  ten  feet  in  thickness,  of  loose  white  sand,  with  thin  laminae  of  gray  clay ; 
this  is  succeeded  by  seventy  feet  of  greenish  and  brownish  sand  overlain  by  seven 
feet  of  coarse  ferruginous  sand,  with  rounded  grains  of  iron-ore  in  the  lower  half  of 
the  bed,  and  by  twelve  feet  of  alternating  sand  and  clay,  making  a  total  of  100  feet. 
There  are  only  very  few  fossils  in  this  group — Myacites  plicata,  Sow.,  and  M.  man- 
dibulata,  Sow. 

XIV.  The  Ferruginous  Bands  of  Black-Gang  Chine  rise  from  the  shore  between  Rocken 
End  and  Black- Gang  Chine,  and  form  the  uppermost  fossiliferous  group  of  the  Lower 
Greensand ;  they  are  composed  of  brown  and  yellow  sand,  with  layers  of  ferruginous 
concretions,  overlain  by  a  bed  of  ferruginous  sandstone,  about  five  feet  in  thickness ;  the 
group  is  about  twenty  feet  in  all,  and  is  the  equivalent  of  the  zone  of  Lower  Greensand  at 
Parham  Park,  and  other  places  in  Sussex,  and  near  Sandgate  in  Kent.  The  sands  in  this 
group  are  fossiliferous  throughout,  and  the  species  identical  with  those  found  in  the  Perna 
bed  and  Cracker  rocks  at  the  bottom  of  the  section. 


6  GAULT. 

XV.  The  Tipper  Clays  and  Sand  Rock  consist  of  forty  feet  of  dark  clay  with  pyrites, 
separated  by  eighteen  feet  of  white  and  green-coloured  sand  from  a  mass  of  clays  and 
sands  sixty  feet  thick.  The  bed  47  of  this  group  is  dug  near  Rocken  End  for  the 
manufacture  of  glass ;  it  contains  no  fossils. 

XVI.  Various  Sands  and  Clay  constitute  the  remainder  of  the  section  ;  they  measure 
about  120  feet  in  thickness,  and  are  overlain  by  the  Gault. 

The  Lower  Greensand  represents  the  upper  portion  of  the  rocks  known  as  the 
Terrain  Neoconiien  of  MM.  Thurmann  and  d'Orbigny ;  Terrain  Jurassique  superieur  of  M. 
Matheron  ;  Couches  adosse'es  au  Jura  of  Von  Buch  ;  Formation  Waldienne  et  Neocomienne 
of  I\IM.  Dufrenoy  and  Elie  de  Beaumont ;  Calcaire  a  Sjmtaiiyues,  L'Argile  ostreene,  of 
M.  Cornuel ;  Arr/iles  tegulines  et  gres  vert  and  "  Terrain  Neocomien  "  (Wealden)  of  M. 
Leymerie.  The  French  geologists  consider  the  Wealden  clay  and  Hastings  sand  as  the 
inferior,  and  the  Lower  Greensand  the  superioi-,  portion  of  their  Neocomien,  whilst  English 
geologists  describe  the  Wealden  and  Lower  Greensand  as  distinct  formations. 


THE  GAULT. 

In  several  coast-sections  the  Gault  is  seen  separating  the  Lower  from  the  Upper 
Greensand ;  this  bed  of  dark  clay  is  called  "  the  blue  slipper,"  from  the  tendency  of  the 
overlying  strata  to  form  landslips  by  gliding  over  its  surface.  The  charming  scenery  of 
the  Undercliff  has  been  in  a  great  measure  produced  by  the  foundering  of  the'Upper 
Greensand  and  Cretaceous  rocks  over  the  Gault  clay  ;  the  rain-water  having  saturated  these 
porous  beds,  bursts  forth  in  springs,  which  wet  the  surface  of  the  clay,  and  occasions 
slips  of  the  superincumbent  strata.  A  rich  fertile  soil  is  thus  formed  upon  a  broad  terrace 
of  stiff  clay,  exposed  to  the  south,  and  sheltered  from  the  north  by  a  high  mural 
escarpment  of  Upper  Greensand.  Under  these  favourable  physical  conditions  vegetation 
springs  up  in  great  luxuriance,  on  a  natural  terrace  high  above  the  sea,  producing  a 
coast-scene  unequalled  in  beauty  in  the  British  Isles. 

The  Gault  is  about  100  feet  in  thickness,  and  in  the  Isle  of  Wight  contains  few  fossils, 
as  Inocerainus  sulcatus,  Sow.,  and/,  concentricus.  Sow.  ;  near  Folkstone  and  Charmouth  it 
lias  yielded  many  beautifid  shells  in  high  preservation.  I  shall  figure  some  rare  Echinidce 
from  this  bed  at  Folkstone. 

The  Bed  Chalk  is  a  remarkable  stratum,  supposed  to  be  the  equivalent  of  the  Gault ; 
it  is  limited  both  in  thickness  and  extent,  for  if  we  take,  says  the  Rev.^T.  Wiltshire,  one 
hundred  feet  as  its  maximum  and  four  feet  as  its  minimum  thickness,  and  100  miles  as  its 
extreme  length,  we  shall  not  be  far  from  the  truth.  It  is  said  to  be  peculiar  to  the  English 
Chalk.  It  is  well  exposed  at  Speeton,  near  Filey,  on  the  Yorkshire  coast,  and  at  Hunstanton 
Cliff,  near  Lynn,  Norfolk  ;  in  both  localities  it  is  a  red  calcareous  rock,  deeply  coloured  by 


RED  CHALK. 


the  peroxide  of  iron,  and  containing  minute  siliceous  grains,  and  small  pebbles  of  chal- 
cedony, quartz,  flint,  &c.  This  rock  from  Hunstanton  yielded  by  analysis  carbonate  of 
lime,  with  a  little  alumina,  82'3  ;  peroxide  of  iron,  6"4  ;  silica,  11'3  =  ;  100. 


Hunstanton  Cliff',^  of  which  the  annexed  woodcut  gives  an  idea,  consists  of  five 
different  beds — 1st,  the  uppermost,  or  white  chalk,  is  forty  feet  thick ;  2nd,  bright-red 
chalk,  four  feet ;  3rd,  yellow  sandy  bed,  ten  feet ;  4th,  a  dark  brown  pebbly  stratum,  forty 
feet ;  and  5th,  a  dark-coloured  bed,  almost  black,  twenty  feet. 

These  divisions  at  Hunstanton,  the  Rev.  T.  Wiltshire  states,  do  not  run  into  each  other, 
but  are  quite  distinct ;  the  red  chalk  is  as  clearly  separated  from  the  white  as  though  the 
one  had  been  covered  by  a  broad  band  of  paint,  and  the  same  remark  holds  true  of  the  others. 
When  the  sun  shines  upon  the  cliff,  and  lights  up  the  bright  white,  bright  red,  the  pale 
yellow,  and  the  dark  brown  and  black,  and  casts  a  shadow  over  the  mass  of  gaily  tinted 
materials  at  the  base,  a  picture  is  produced  not  easy  to  be  surpassed  in  beauty,  and 
certainly  not  to  be  fully  appreciated  unless  it  is  seen. 

The  Red  Chalk  is  very  fossiliferous,  containing  Ammonites,  Belemnites,  Brachiopoda, 
Echinidse,  and  Corals. 

In  compliance  with  my  request,  ray  friend  the  Rev.  T.  Wiltshire,  F.G.S.  has  kindly 
sent  me  the  following  note,  embodying  his  latest  observations  on  the  Red  Chalk  at  Speeton.' 

"  In   answer  to  your  inquiry  respecting  the  natural  section  of  the  Red  Chalk  at  the 

1  For  ample  details,  see  the  Rev.  Thos.  Wiltshire,  on  the  'Eed  Chalk  of  England.' 
'  To   this  gentleman's  kindness  I  am  likewise  indebted  for  the  above  woodcut,  copied  from  a  water- 
colour  drawing  ii  his  collection. 


S  SPEETON  CLAY. 

most  northern  extremity  of  that  bed  in  England,  viz.,  in  the  neighbourhood  of  the  little 
Yorkshire  village  of  Speeton,  I  send  you  a  few  scanty  notes.  On  my  first  visit  to 
Speeton,  some  years  since,  I  imagined,  as  I  suljsequcntly  described  in  the  second  volume 
of  the  'Geologist  Magazine,'  and  in  the  'Proceedings  of  the  Geologists'  Association'  for 
1859,  that  the  Red  Chalk  in  Yorkshire  consists  of  a  couple  of  bands  of  a  highly  coloured 
marl,  of  about  thirty  feet  in  thickness  from  top  to  bottom,  and  that  its  fossils  are  of  such 
forms  as  to  imply  a  close  relationship  with  Gault  species.  This  opmion  I  derived  from  seeing 
the  section  in  a  gulley  to  the  east  of  the  village ;  but  subsequent  investigations  made  upon 
the  shore  under  the  clifT,  at  a  mile  or  more  from  the  ravine,  showed  me  that  my  former  ob- 
servations were  slightly  incorrect,  and  that  the  Red  Chalk,  in  that  part  of  Yorkshire  at  least, 
contains  two  more  additional  coloured  bands,  and  that  its  total  thickness  from  top  to  bottom 
is  not  less  than  100  feet,  and  that  its  upper  portion  belongs  to  the  Lower  Chalk  series. 

"  The  highest  bed  of  Red  Chalk  at  Speeton  may  be  seen  rising  from  the  beach  at  a 

very  gentle  inclination,  at  about  a  mile  and  a  half  to  the  south-east  of  the  gulley.     This 

bed,  which  is  of  varying  thickness  throughout  its  course,  may  be  estimated  as  being  on 

an  average  about  five  feet  thick ;  it  is  of  a  pale  pink  colour,  very  hard,  and  presents  a 

strongly   marked    appearance   from    the    white  chalk,   above  and  below,  with  which  it 

is  in   contact.     The  fossils  found  in  it  are  Bhjnchonella  Mantelliana,   Gri/ph(ea  vesicu- 

laris,  Biscoidea  cylindrica,  Holader  subglobosus,  Spines  of  Cidaris,  Spines  of  Dindema 

small  vertebrae  and  teeth,  together  with  a  considerable  number  of  Terebratulin^  graciles. 

Above   this   bed,   in    the  white  chalk,   are  found  Holaster  subglobosus  and  Ammonites 

peramplus.     The  pink  band  just  mentioned  is  followed  by  a  greenish-yellow  chalk,  about 

forty  feet  thick,  almost  destitute  of  organic  remains,  except  fragments  of  Inocerami,  and 

marked  by  numerous  thin  layers  of  marl,  not  unlike  those  met  with  in  the  Lower  Chalk  of 

Sussex.    The  next  bed  in  descending  order  is  one  of  a  light  pink  colour,  about  three  feet  in 

thickness,  likewise  destitute  of  fossils,  with  the  exception  of  fragments  oi  Inocerami.     This 

is  followed  by  another  stratum  of  greenish-yellow  chalk,  about  nine  feet  thick,  containing 

small  GryphcBce,  and  Terebratulce  semiglobosa,  and  PeUasles,  but,  like  the  two  preceding 

beds,  generally  unfossiliferous.     The  greenish-yellow  chalk  is  succeeded  by  five  feet  of 

white  and  red  chalk,  in  thin  bands,  very  deficient  in  organic  remains,  and  this  rests 

upon  a  pale-red  band,   about  seven  feet  thick.     Li  the  upper  part  of  this  last  seven  feet 

of    red   material   are    many    Vermicularicp.   umbonatce,   and   in   its   lower   portion    many 

small  TerebratulcB  and  Inocerami.     About  ten  feet  of  greenish-white  chalk,  somewhat 

hard,  is  the  next  bed,  in  which  few  fossils  are  to   be  noted  except  a  Terebratula  and  a 

bone  or  two  of  a  Star-fish.     \\\  all  these  strata  enumerated  there  is  a  marked  absence  of 

Belemnites,  but  in  the  succeeding  and  last  bed,  one  of  a  bright-red  colour,  and  more  than 

thirty  feet  thick,  they  become  exceedingly  abundant.     This  red  band  -is  the  one  from  which 

most  of  the  Red  Chalk  fossils  from  Speeton  are  derived  ;  it  is  exceedingly  fossiliferous.     Ii] 

its  uppermost  portion  very  large  Terebrafido:  may  be  obtained,  and  generally  inany  of  an 

ordinary  size;    at  about  twenty  feet  below  its  commencement,  Belemnites,  Pentacrim, 


SPEETON  CLAY.  9 

and  sjMiies  of  a  Cidaris  occur,  wliicli  appear  to  be  distinct  from  the  Cidaris  spines,  ninety-four 
feet  above,  in  the  pink  band.  There  are,  moreover,  no  traces  of  IMastcr  suhyhhosm  nor 
Discoidea  cylindrica  in  this  bright-red  bed ;  and  Ammonites  cannot  be  seen,  though  so 
numerous  in  the  Speeton  Clay,  upon  whicli  it  rests.  This  red  band  gradually  becomes 
nodular,  and  of  a  bluish  cast,  and  gradually  merges  into  the  Speeton  Clay. 

"  Inland  the  Yorkshire  beds  put  on  a  somewhat  difierent  appearance,  for  on  the  escarp- 
ment of  the  Wolds,  as  at  Great  Givendale,  the  beds  of  Red  Chalk  abound  in  pebbles 
and  in  Terehratitla  bipUcafce,  a  feature  that  is  absent  at  Speeton,  though  conspicuous  at 
Hunstanton,  in  Norfolk. 

"A  careful  inspection  of  the  fossils  derived  from  the  Red  Chalk  series  of  Yorkshire  and 
Norfolk  shows  that  the  two  extremities  of  the  bed  are  very  distinct  in  character,  and  have  not 
much  in  common,  and  that  the  southern  stratum  is  a  moi'e  littoral  deposit  than  the  northern." 

l\Iy  friend  John  Leckenby,  Esq.,  E.G.S.,  of  Scarborough,  having  studied  critically  the 
fossils  of  the  Speeton  Clay,  has  kindly  supplied  the  following  note  on  that  formation,  from 
which  it  appears  that  until  now  the  true  relations  of  this  deposit  have  not  been  clearly 
understood. 

"  The  Speeton  Clay  of  Yorkshire,  besides  many  minor  subdivisions,  presents  two 
important  and  well-marked  sections ;  well-marked  lithologically,  still  more  so  by  their 
fossils.  The  line  of  separation  midway,  or  nearly  so  in  the  series,  is  also  distinct  and  clear, 
with  no  passage-beds  indicating  a  transition  from  one  set  of  conditions  to  another.  Its 
entire  thickness  cannot  be  less  than  400  feet,  but  in  consequence  of  the  denudation  of  the 
inclined  edges  of  its  beds  it  nowhere  presents  a  continuous  section  of  more  than  150  feet. 

"  The  lower  division  is  characterized  in  its  upper  beds  by  Ammonites  and  Gas- 
teropods,  which  I  at  one  time  felt  inclined  to  refer  to  the  O.xfordian  system,  and  many 
palaeontologists  yet  contend  that  the  thick  coronated  Ammonites  v/hich  here  abound 
belong  to  the  Oxfordian  group.  Without,  however,  doing  violence  to  our  preconceptions 
of  stratigraphical  relations,  we  shall  find  that  they  approach  much  more  nearly  to 
Portlandian  types,  as  figured  by  d'Orbigny;  &\\(\Aiii.  (Jraye-w/z^^s  cannot  be  distinguished 
from  a  common,  but  unpublished  form,  in  the  Speeton  Clay.  In  the  lowest  beds  of 
this  lower  division  are  found  Am.  inpUcatus,  Am.  cxcavatus  (var.  aUernatus,  Von  Buch), 
with  univalve  and  bivalve  shells  identical  with  species  which  I  have  obtained  from  the 
Kimmeridge  Clay  of  Lincolnshire,  in  a  railway-cutting  near  Brigg.  The  line  of  demarcation 
before  referred  to  is  characterized  by  a  thickish  band  of  pseudo-coprolites,  and  by  many 
remains  of  Saurian  animals ;  it  would  appear  that  here  there  has  been  a  period  of  repose, 
during  which  the  Saurian  dwellers  upon  a  shallow  reef  disported  themselves,  and  that  we 
have  a  well-marked  division  between  the  close  of  the  Jurassic  and  the  commencement  of 
the  Cretaceous  period.  A  large  and  almost  perfect  example  was  lately  procured  and  is  now 
in  the  possession  of  Right  Hon.  Lord  Londesborough,  the  lord  of  the  manor  of  Speeton. 

"  The  habit  of  referring  the  whole  of  the  Speeton  Clay  of  Yorkshire  to  the  Cretaceous 
period,  in  deference  to  established  authorities,  has  hitherto  prevented  a  clear  reading  of 

2 


10  UPPER  GREENSAND. 

the  evidence  furnished  by  its  fossils,  and  from  the  fact  of  so  many  of  its  Ammonites  of 
the  Oolitic  type  being  found,  not  in  situ,  but  in  boulders,  has  led  to  the  inference  of  the 
existence,  at  some  remote  period,  in  Filey  Bay,  of  great  beds  of  Oxford  Clay  similar  in 
character  to  the  Oxford  Clay  of  the  south  of  England. 

"  The  Ammonites  can,  however,  with  much  more  propriety,  be  referred  to  Portlandian 
types,  and  the  wasted  beds  which  have  furnished  the  boulders  doubtless  pertain  to  the 
•same  epoch. 

"  Above  the  line  of  Saurian  remains  alluded  to,  all  the  fossils  belong  to  the  Cre- 
taceous type ;  and  amongst  the  exact  representations  of  a  Neocomian  fauna  many  others 
are  found  which  in  general  features  closely  resemble  them.  Amongst  the  former,  Ammonites 
Dcshayesii,  Leym.,  and  Vermicularia  Sowerhii  may  be  mentioned,  while  Crioceras  JBeanii, 
Phil.,  cannot  easily  be  distinguished,  if  at  all,  from  C.  Cornuelianum,  d'Orb. 

"  If  we  seek  for  the  equivalents  of  the  Upper  Greensand  in  the  Speeton  Clay,  we  must  do 
so  rather  in  the  lower  beds  of  Red  Chalk  which  overlie  that  deposit  than  in  the  clay  itself; 
and  the  frequent  presence  therein  of  Inoceramiis  Coqiiandianus,  d'Orb.,  favours  this  view. 

"  The  junction  of  the  lowest  beds  of  Speeton  Clay  with  the  Coralline  Oolite  cannot 
be  traced  along  the  coast,  but  may  be  seen  at  some  distance  inland,  near  the  village 
of  Grimstou,  one  of  the  stations  on  the  line  of  railway  between  Malton  and  DritTiekl." 

The  Gault  is  the  equivalent  of  the  Eta^e  Albion  of  d'Orbigny,  and  tlie  Gaulf  of  the 
■Germans. 

THE    UPPER   GREENSAND. 

This  formation  forms  an  important  feature  in  the  physical  geology  of  the  Isle  of 
"Wight ;  in  Compton  and  Sandown  Bays  it  is  seen  in  its  relative  position  to  the  Lower 
Greensand  below  and  the  Clixilk  above,  and  in  the  Undercliff  it  forms  a  bold,  mural, 
light-coloured  escarpment,  with  rugged  lines  of  cherty  beds,  producing  a  fine  effect  above 
the  rich  foliage  which  clothes  the  undercliff.  According  to  H.  W.  Bristow,^  Esq.,  F.G.S., 
tlie  Upper  Greensand  under  St.  Catherine's  Down  is  about  155  feet  thick;  the  lower  fifty- 
five  feet  consist  of  "bluish,  sandy,  micaceous  beds,  throwing  out  water  at  their  janctiou 
with  the  Gault,  and  passing  upwards  into  yellowish-gray  sand,  also  micaceous,  with 
sandstone  and  some  chert,  forty  feet  thick.  Sandstone  and  chert  imbedded  in  sand 
make  up  the  greater  part  of  the  rest  of  the  section,  the  middle  portion  of  which  is 
mostly  blue  chert  based  upon  seven  feet  of  sandstone,  inclosing  a  bed  of  freestone  four 
feet  thick,  whilst  the  uppermost  fifteen  or  twenty  feet  consist  of  calcareous  sandstone, 
forming  a  vertical  face  at  the  summit  of  the  cliff." 

In  the  island  the  remains  of  Echinidoe  are  not  abundant  in  these  beds ;  the  Upper  Green- 
sand, near  Warminster  and  Devizes  (Wilts) ;  Blackdown  (Devon)  ;  and  near  Charinouth 
(Dorset),  and  Cambridge,  are  the  best  localities  for  the  fossil  Echinodermata  of  this  formation. 
1  "  Jlemoirs  of  the  Geological  Survey,"  the  '  Geology  of  the  Isle  of  Wight,'  p.  24. 


LOWER  CHALK,  AND  CHALK-MARL.  11 

CHLORITIC  MARL. 

At  the  base  of  the  Chalk,  and  dividing  that  formation  from  the  Upper  Greensaud,  is 
a  remarkable  fossiliferous  bed,  full  of  green  specks  of  silicate  of  iron,  and  called,  in 
consequence,  Chloritic  Marl,  which  at  St.  Catherine's  Down  measures  five  feet  in  thick- 
ness. This  Marl  is  characterized  by  a  suite  of  fossils,  some  of  which,  as  Scc/jMtes  iequalls, 
Sow.,  here  appear  for  the  first  time,  and  seem  to  be  special  to  the  bed ;  with  these  are 
found  Ammonites  varians.  Sow.,  Amm.  sjjieiidens,  Sow. ;  several  Protozoa  belonging  to 
the  genera  Spoiiffia,  SipJionia,  and  Sci/pJda ;  Echinodermata,  as  Ananchjtes  lavis,  Deluc ; 
Catopijgus  carinafus,  Goldf. ;  and  Biscoidea  subuculus,  Leske ;  together  with  several  species 
of  MoLLUscA.  The  same  stratum  occurs  near  Chardstock,  from  whence  I  have  obtained 
many  fine  specimens  of  Psciidodiadcma  tumidum,  Eorbes,  P.  siibnudim,  Ag.,  Pedinopsis, 
Holedypm,  and  several  other  species,  most  of  which  are  common  to  this  rock  and  the 
Upper  Greensand,  of  which  it  probably  forms  the  uppermost  bed. 

The  Upper  Greensand  appears  to  correspond  to  the  Glaucoiiie  craycuse  of  the  French, 
the  Tourtiu  of  the  Belgians,  the  Grunsand  of  the  Germans,  and  the  Etagc  Cenomanicn  of 
d'Orbigny. 

THE  LOWER  CHALK,  AND  CHALK-MARL. 

The  Chalk  formation  occupies  a  large  area  in  the  Isle  of  Wight,  and  in  the  southern 
and  eastern  parts  of  England.  It  consists  of  nearly  piu-e  carbonate  of  lime,  and  in  many 
cases  is  almost  entirely  composed  of  microscopic  shells,  either  fractured  or  entire.  My  friend 
H.  C.  Sorby,  Esq.,  F.G.S.,  by  preparing  thin  slices  of  chalk  on  slides  of  glass  for  microscopic 
examination,  has  shown  that  many  beds  of  that  rock  consist  of  from  90  to  95  per  cent, 
of  the  cases  of  Forcminifera,  and  of  comminuted  shells.  The  chief  difference  between 
the  Upper  or  soft  white  Chalk,  and  the  Lower  or  hard  Chalk  is  caused  by  the  filling  up  of 
the  cavities  of  the  shells  by  calcite  or  crystalline  carbonate  of  lime,  wlierc  it  has  pro- 
bably been  deposited  by  infiltrating  water,  which  has  carried  away  some  of  the  lime  in 
percolating  through  the  higher  beds.  The  Chalk  formation  is  divided  into  Chalk-marl  at 
the  base.  Lower  or  hard  Chalk  without  flints,  and  soft  or  Upper  Chalk  with  flints.  In  the 
Isle  of  Wight  the  whole  formation  is  1300  feet  in  thickness,  whilst  in  England  it  varies 
from  600  to  900  feet. 

The  Lower  Chalk  near  Dover  is  of  a  grayish  colour,  and  much  indurated  in  parts.  It 
is  very  rich  in  Echinida,  and  contains  several  new^  species.  Unfortunately,  many  of  the 
finest  specimens  are  impregnated  with  iron,  and  perish  by  the  decomposition  of  the 
pyrites.  At  Lewes,  in  Sussex,  it  is  a  hard,  close-grained  rock,  with  an  earthy  fracture, 
and  contains  many  urchins  in  fine  preservation. 

The  following  section,  by  the  Rev.  W.  D.  Couybeare,  of  the  Clialk  cliff's  near  Dover, 


12  WHITE  CHALK. 

exhibits  so  well  the  position  and  relation  of  the  Gray  Chalk,  which  contains  so  many 
fine  Ecliinidee,  that  I  have  introduced  it  here  for  reference.  The  strata  lie  in  the  following 
descending  order,  and  are  collectively  about  820  feet  thick. 

1st.  The  Chalk  n-UJt   'niiiiierous  fints ;  it  is  about  350  feet  thick,  and  may  be  thus 
divided  : 

I.  With  few  organic  remains. 

II.  A  Ijed  consisting  chiefly  of  organic  remains  in  wliich  numerous  flints  of 

peculiar  forms  are  interspersed ;  and  a  iew  beds  of  flints  run  along  it. 

2nd.   The  Chalk  with  few  Jlhits.     This  stratum  is  about  130  feet  thick. 
3rd.  The  Chalk  xcithout flints  is  140  feet  thick,  and  consists  of — 

I.  A  stratum  containing  very  numerous  and  thin  beds  of  organic  remains, 

90  feet  thick. 

II.  A  stratum  about  50  feet  thick,  witli  few  organic  remains. 

4th.  The  Graij  Chalk.  This  is  estimated  to  be  not  less  than  200  feet  in  thickness, 
and  is  that  from  which  has  been  collected  most  of  the  fine  specimens  of  Cidaris 
Bmccrhankii,  Forb. ;  Pseudodiadema  ornatum,  Forb. ;  F.  fumidum,  Forb.  ;  P. 
variolare,  Brong.;  P.  Brongniarti,  Ag. ;  P.  Mackiei,  "Wowd.,  Salenia  Austeni, 
Forb. ;  S.  Clurkii,  Forb.  ;  S.  gihha,  Forb. ;  S.  granulosa',  Forb. ;  and  5'.  peta- 
lifera,  Defr.,  with  other  specimens  of  Chalk-marl  species. 

The  Lower  Chalk  and  Chalk-marl  are  represented  on  the  Continent  by  the  Untcre 
Kreide  and  Planer  of  the  Germans,  the  Craie  tuffeau  of  the  Fi'ench ;  and  tlie  Etage 
Turomcn  of  d'Orbigny. 

THE  AVHITE  CHALK. 

The  uppermost  ]5ortion  of  the  Cretaceous  formation  extends  across  the  island  in  an  east 
and  west  direction,  from  the  Needles  to  Culver  Cliff,  and  all  its  beds  are  fully  exposed  in 
several  magnificent  coast-sections ;  as  these  beds  are  nearly  vertical  or  highly  inclined 
at  Alum  and  Scratchells  Bays  on  the  east,  and  at  Culver  Cliff's  on  the  west,  the  sub- 
divisions of  the  whole  Cretaceous  formation,  and  the  way  the  beds  pass  into  each  other, 
may  be  most  satisfactorily  ascertained.  The  bands  of  flints  are  well  displayed  in  Scratchells 
Bay  and  Culver  Cliffs,  and  there  is  a  flne  exposure  of  vertical  Chalk  strata  in  a  pit  on 
Brading  Down ;  in  all  these  localities,  and  many  others  which  it  is  imnecessary  to 
enumerate,  tlie  flints  appear  as  parallel  layers  at  certain  intervals  in  the  strata,  presenting 
a  striking  contrast  from  their  blackness  to  the  snowy  aspect  of  the  Chalk  with  wliicli  they 
are  interstratified. 

"In   consequence  of  the   high  angle  at  which  the  Chalk  dips  throughout  the  greater 


WHITE  CHALK.  13 

part  of  its  range  from  west  to  east,  the  surface  occupied  by  it  is  very  inconsiderable  com- 
pared with  that  of  most  of  the  other  strata  above  and  below  it,  but  its  horizontal  extension 
becomes  greater  in  proportion  as  the  inclination  of  the  strata  diminishes.  For  this  reason, 
from  Alum  Bay  to  Mottestone  Down,  and  from  Carisbrook  to  Culver  Cliff,  between  which 
intervals  the  Chalk  is  nearly  vertical,  it  constitutes  a  mere  ridge  of  high  land,  which  is  scarcely 
a  quarter  of  a  mile  broad  in  Aston  Down ;  but  between  Mottestone  Down  and  Carisbrook, 
where  the  strata  are  less  inclined,  the  width  of  the  Chalk  exceeds  three  miles. "^ 

"  The  flints  in  the  Chalk  are  for  the  most  part  irregular  in  shape,  but  they  sometimes 
constitute  tabular  layers  coincident  with  the  stratification,  or  else  filling  cracks  and  joints. 
Those  flints  which  occur  parallel  with  the  bedding  are  of  a  different  age  from  those  filling 
the  cracks  and  joints.  The  former  are  derived  from  siliceous  matter,  frequently,  and 
perhaps  in  most  instances,  deposited  contemporaneously  with  the  calcareous  sediment  of 
which  the  Chalk  is  composed,  around  sponges  and  other  organized  bodies,  the  forms  and 
internal  structure  of  which  are  still  preserved.  The  latter,  on  the  contrary,  are  of  more 
recent  origin,  having  been  carried  by  percolating  water  holding  silica  in  solution  into  cracks 
and  joints  formed  by  the  Chalk  during  or  after  its  solidification.  The  tabular  bands 
of  flint  filling  cracks  and  joints  are  therefore,  and  as  might  be  expected  on  the  last  suppo- 
sition, unfossiliferous,  instead  of  abounding  in  fossils,  as  is  the  case  with  the  other  system 
of  flints."  "  In  the  upper  part  of  the  Chalk,  where  the  beds  are  the  most  highly  inclined, 
the  flints,  which  appear  to  be  whole  when  viewed  in  sifif,  are  found,  on  closer  examination, 
to  be  nearly  all  broken  so  that  when  extracted  from  the  quarry  they  fall  to  pieces." 
"  Shattered  flints  may  be  observed  in  the  large  chalk-pits  south  of  Newport,  and  on  Avreton 
Down ;  also  on  Ashley  Down,  where  the  Chalk  is  rather  hard  (as  is  most  frequently  the  case 
where  it  is  inclined  at  a  high  angle),  dipping  G.j°  in  a  direction  slightly  east  of  north. "^ 

The  AVhite  Chalk  contains  many  species  of  Echinida%  of  which  the  most  common  are 
Ecldnocorys  vul(jariH,  Breyn. ;  Galerites  albo-t/alerus,  Lamck. ;  Micrasfer  cor-anr/uinuhi, 
Klein ;  Cidaris  davi(/era,  Konig ;  Cidaris  sceptrifcra,  Mant. ;  Cidaris  subvesiculosa, 
d'Orbigny,  and  several  other  forms,  to  be  figured  and  described  in  the  following  pages. 

The  "  Upper  White  Chalk  with  flints  "  of  English  authors  corresponds  to  the  Crair 
Handle  of  the  French,  the  Obere  Kreide  of  the  Germans,  and  the  Etarje  Sinonicn  of 
d'Orbigny. 

Besides  the  localities  already  mentioned,  it  is  well  exposed  and  very  fossiliferous  at 
Lewisham,  Grays,  Northfleet,  Norwich,  Brighton,  Dover,  and  other  places  in  the  counties 
Sussex  and  Kent,  and  at  Flamborough  Head,  on  the  Yorkshire  coast. 

The  following  table  exhibits  at  a  glance  the  subdivisions  of  the  Cretaceous  formations, 
with  their  lithological  characters,  chief  localities,  and  foreign  equivalents,  so  as  to  afford 
an  easy  reference  to  the  stratigraphical  distribution  of  the  species  of  Eddaid<B  in  each  of 
the  beds. 

1  Eristow,  on  the  "  Geology  of  the  Isle  of  Wight,"   'Mem.  of  the  Geol.  Suit.,'  p.  28. 
^  Brislow,  ibid.,  p.  31. 


14 


CRETACEOUS  GROUP. 


A  TABLE   OF   THE   CRETACEOUS   GROUP   OF   ENGLAND. 


SUBDIVISIONS. 


LITIIOLOGICAL  CHARACTER. 


LOCALITIES.         FOREIGN  EQUIVALENTS. 


Upper  Chalk 


o 

pi 
o 

o 
o 

Eh 

w 
Pi 
o 

H 


Lower   Chalk,   and 
Chalk-marl. 


Chloritic  BIarl 


Upper  Green sand 


Nearly  pure  carbonate  of  lime,  with 
minute  fragments  of  Shells  and 
Foraminifera,  forming  a  white  or 
yellowish-white,  soft  Chalk ;  the 
upper  beds  of  v/hich  are  interstra- 
tified  with  laj'ers  of  flints,  or  tabu- 
lar layers  of  dark  silex  coincident 
■with  the  stratification. 

Hard  Chalk,  without  flints,  sometimes 
passing  into  Chalk-marl  or  hard 
Grav  Chalk. 


Light-coloured  marl,  full  of  green 
specks  of  silicate  of  iron,  with 
numerous  fossils. 


Siliceous  sand,  or  nearly  calcareous 
sand,  with  grceu  grains  ;  the  rock- 
often  contains  nodules  of  chert  and 
masses  of  limestone. 


Isle  of  Wight, 
Lewisham,  Grays, 
Northfleet,  Nor- 
wich, Brighton, 
Dover,  Flam- 
borou2:h  Head. 


Crate  blanche,  French. 
Obere  Kreide,  Germans. 
■  Etage  Sinonien,  d'Orb. 


Dover,  Folkestone, 
Lewes  (Sussex), 
Swafiham,  Nor- 
wich. 

Chard,  Chardstock, 
St.  Catherine's 
Down,  Isle  of 
Wieht. 


TJntere  Kreide,Qiexm&xis, 
.  Planer,  Germans. 
Craie  tnffeau,  French. 
Etaye  Tiironien,  d'Orb. 


crayeuse. 


Gault . 


'l 


Dark-blue  tenacious  clay,  sometimes 
marly,  with  some  concretions. 


Warminster,     De-  / 
vizes,ChuteFarm, 
Petersfield,  Cam- 
bridge,        Char- 
raouth,  Dorset. 

Isle      of      Wight,  1 
Folkestone,  Char- 
mouth. 


Glauconie 
French. 
\  Tourtia,  Belgians. 
GrUnsand,  Germans. 
Etage  Cenomanien,  d'Orb. 


Red  Chalk 


A  thin  bed  of  hard,  red  Chalk,  deeply  a 

coloured  by  the  pero.xide  of  iron,  Hunstanton  Cliflf, 
and  having  numerous  small  sili-  \  -Noriolk  ;  riley 
ceous  grains  and  pebbles  of  quartz,  1  "^y'  Yorkshire. 
&c.,  strewed  throughout  the  mass. 


^  Gault,  Germans. 
Etage  Albieii,  d'Orb. 


Speeton  Clay. 
[Upper  part.] 


^  Lower  Green  sand  . 


'A  grayish-coloured  clay,  the  upper 
portion  containing  Neocomian,  tiie 
lower  portion  Poitlandiau  species 
of  fossil  shells. 

A  great  areuacous  formation,  com- 
posed of  ferruginous  sands  with 
green  grains,  dark-coloured  clays 
and  clayey  sands ;  and  in  some 
localities,bands  of  limestone  known 
as  Kentish  Rag. 


Filey   Bay,   York- 
shire. 


Isle      of      White, 
Folkestone, 
Ilythe,         Maid- 
stone. 


Terrain  NSocomien  sitpc- 
rieur     of     Swiss     and 
French. 
Etage  Aptien,  d'Orb. 


ECHINODERMATA.  15 


Classification  op  the  ECHINODERMATA. 

The  name  Echinodermata  was  given  by  Klein,  in  1734,^  to  the  shells  of  Sea- 
iii'cliins  called  Echini.  Brnguicre^  subsequently  gave  the  name  Echinodermata  to  that 
division  of  the  animal  kingdom  which  comprised  the  Star-fishes  and  the  Sea-urchins. 
Cuvier^  included  in  his  class  Eciiinodermes,  with  Asferias  and  Echinus,  the  Holothitria, 
animals  destitute  of  the  prickly  skin  of  the  more  typical  forms,  and  which  had  many 
external  affinities  with  some  Mollusca ;  and  subsequently,  in  his  '  Regno  Animal,'*  he 
grouped  in  this  class  les  Eciiinodermes  sans  pieds,  forming  the  order  Sipunculida,  which 
connect  the  Radiata  with  the  Annulose  Articulata. 

The  Echinoderms  are  highly  organized  animals,  for  the  most  part  covered  with  a 
coriaceous  integument.  In  several  orders  it  is  strengthened  with  numerous  calcareous 
pieces,  which  together  form  a  complicated  skeleton.  The  external  sm'face  of  the  skin,  in 
many  families,  develops  spines  of  various  forms,  which  serve  as  instruments  of  defence 
or  locomotion  to  the  creatures  possessing  them.  By  far  the  largest  number  of  these 
animals  have  a  complicated  system  of  vessels  for  circulating  water  through  their  bodies. 
These  aquiferous  canals  are  intimately  connected  with  the  life  and  motion  of  the  animal ; 
by  means  of  this  vascular  water-system  most  of  the  typical  groups  erect  those  remarkable 
suckers  which  protrude  in  rows  from  different  divisions  of  the  body ;  in  the  Echinoidea 
they  escape  through  holes  in  the  poriferous  zones,  and  in  the  Asfcroidca  pass  through 
apertures  between  the  small  plates  forming  the  middle  of  the  rays  ;  whilst  in  the  Sipun- 
culida these  organs  are  altogether  absent. 

No  class  of  the  animal  kingdom  more  clearly  exhibits  a  gradation  of  structure  than 
the  Echinodermata ;  for,  whilst  some  remain  rooted  to  the  sea-bottom,  and  in  this  sessile  con- 
dition resemble  the  Poli/pifera,  others,  clothed  in  prickly  armom*,  and  exhibiting  the  true 
rayed  forms  characteristic  of  the  central  groups,  conduct,  through  a  series  of  beautiful 
gradations,  to  soft  elongated  organisms,  whose  outline  mimics  the  Ascidian  Mollusca, 
whilst  others  exhibit  the  long  cylindrical  body,  annulose  condition  of  the  skin,  and 
reptatory  habits  of  the  Apodous  Annelida. 

With  so  fertile  a  field  for  investigation,  it  is  not  surprising  that  the  minute  anatomy 
of  the  Echinodermata  should  have  engaged  the  attention  of  some  of  the  most  distinguished 
zoologists  of  our  age,  and  have  yielded  fruits  which  the  physiologist  reckons  as  amongst 
the  most  marvellous  contributions  to  morphological  science. 

1  'Naturalia  Dispositio  Ecliinodermatum,'  Jacobl  Theodori  Klein,  1/34. 

2  'Tableau  Encyclopedique  des  trois  U6gaes  de  la  Nature,"  1791. 

^  'Tableau  Elementairc  de  I'llistoire  naturelle  des  Animaux,'  1798. 
*  '  Rfegne  Animal  destiibue  d'apres  son  Organisation,'  1834. 


16  ECHINODERMATA. 

Tlie  class  Ecliiiiodermata  is  divided  into  eight  orders,  which,  in  descending  sequence, 
may  he  thus  arranged  : 


1.  SiPCNCULOIDEA. 

2.  HOLOTHUKOIDEA. 

3.  EciIlNOIDEA. 

4.  ASTEIIOIDEA. 


5.  Ophiukoidea. 
C.  Blastoidea. 

7.  Cystoidea. 

8.  CltlXOIDEA. 


Order  I.  SiruNCULOiDEA — form  the  apodal  Annulose  Echinoderms ;  they  have  a 
long  cylindrical  body,  divided  into  rings  by  transverse  folds  of  the  inlegument;  they  have 
neither  tubular  suckers  nor  calcareous  parts  developed  in  their  body,  nor  is  it  divided 
into  a  quinary  arrangement  of  longitudinal  lobes ;  some  have  horny  booklets  like  the 
feet  of  many  Annulosa,  which  they  much  resemble ;  their  moutli  is  provided  with  a 
retractile  proboscis,  and  surrounded  by  small  tentacula,  differing  both  in  structure  and 
arrangement  to  the  homologous  parts  in  the  IMothtria.  In  them  the  type  of  Ttadiaia 
vanishes  and  that  of  Annulosa  appears.     They  are  unknown  in  a  fossil  state. 

Type.     Sipuncidus  edulis,  Pallas. 

Order  ii.  Holothuroidea. — Body  in  general  elongated ;  skin  in  general  soft  and 
leathery,  in  a  few  genera  strengthened  by  calcareous  or  horny  spines.  Five  avenues  of 
suckers  divide  the  body  into  as  many  nearly  equal  segments ;  month  surrounded  by 
plumose  tentacula,  the  numbers  of  which  are  usually  multiples  of  five ;  vent  at  the 
opposite  extremity  of  the  body ;  digestive  organs  consist  of  a  large  intestine,  which  makes 
several  coils  in  passing  through  the  body ;  respiration  performed  by  internal  ramified 
tubes,  like  a  miniature  tree;  locomotion  effected  by  contractions  and  extensions  of  the 
bodv,  and  bv  rows  of  tubular  suckers,  similar  to  those  in  the  Star-fishes  and  Sea-urchins. 
The  softness  of  their  naked  integument  prevents  their  preservation  in  the  stratified  rocks. 

Type.      Cuciimaria  froiuhsa,  Gunner. 

Order  in.  Echinoidea. — Body  spheroidal,  oval,  or  depressed,  enclosed  in  a  test, 
composed  of  twenty  columns  of  calcareous  plates,  with  ten  rows  of  holes  for  the  passage  of 
retractile  tubular  suckers ;  the  surface  of  the  test  is  studded  with  tubercles,  which  have 
jointed  with  them  moveable  spines,  of  various  sizes  and  forms  in  the  different  families, 
and  genera ;  at  the  summit  of  the  test  is  the  apical  disc,  composed  of  give  genital  plates, 
perforated  for  the  passage  of  the  ovarial  and  seminal  tubes,  and  five  ocular  plates  for 
lodging  the  five  eyes.  The  mouth,  situated  always  at  the  under  surface,  is  in  many 
genera  armed  with  five  powerful,  complicated  jaws  and  teeth,  and  in  others  the  peris- 
tome is  edentulous ;  the  vent  occupies  various  different  positions,  sometimes  within  the 
apical  disc  and  surrounded  by  its  elementary  parts,  sometimes  external  to  the  disc,  and 
at  the  upper  surface,  side,  or  base,  the  relative  position  of  the  vent  to  the  disc  affording 


ECIIINODERMATA.  17 

an  important  cliaractev  for  the  subdivision  of  the  order  into  two  primary  groups.  The 
intestine  winds  rounds  the  shell,  attached  by  a  mesentery,  the  surface  of  which,  as  well  as 
the  membrane  lining  the  shell,  is  covered  with  vibratile  cilia. 

Type.     The  common  Sea-urchin,  Echinus  sjihtera,  Milller. 

The  EcHiNoiDEA  arc  represented  by  one  family  in  the  Paljeozoic  rocks,  and  by 
numerous  families  in  the  Mesozoic  and  'J'ertiary  groups,  several  of  which  characterize 
these  great  periods  of  geological  time.     They  likewise  abound  in  our  present  seas. 

Order  iv.  Asteroidea. — Body  stelliform,  depressed,  with  five  or  more  lobes  or 
hollow  arms,  forming  a  continuation  thereof,  and  containing  prolongations  of  the  viscera; 
the  mouth  is  always  inferior  and  central,  and  the  intestine  often  terminates  in  a  vent 
opening  at  the  upper  surface;  in  some  genera  the  vent  is  absent;  rows  of  retractile 
tubular  suckers  occupy  the  ambulacral  areas  in  the  centre  of  the  under  sarftice  of  the 
rays.  Skeleton  complicated,  composed  of  numerous  solid  calcareous  pieces,  variable  as  to 
number,  size,  and  disposition ;  skin  coriaceous,  studded  with  calcareous  spines  of  various 
forms ;  a  madreporiform  plate  on  the  upper  surface,  near  the  angle  between  two  rays ; 
eyes  placed  at  the  extremity  of  the  rays ;  reptation  performed  by  tubular  suckers. 

Type.     The  common  Star-fish,  Urastcr  rubetis,  Linn. 

This  order  is  represented  in  the  Silurian  rocks  by  several  genera.  The  Oolitic,  Cre- 
taceous, and  Tertiary  rocks  contain  many  extinct  forms.  The  existing  species  are  very 
abundant  in  all  our  present  seas. 

Order  v.  Ophiuroidea. — Bpdy  discoidal,  distinct,  depressed,  provided  with  long, 
slender  arms,  in  which  there  is  no  excavation  nor  prolongation  of  the  viscera;  they 
are  special  organs  of  locomotion,  independent  of  the  visceral  cavity,  and  have  spines, 
and  membranous  tentacula  developed  from  their  sides ;  mouth  always  below  and  central, 
serving  at  the  same  time  as  the  vent.  Skeleton  complicated,  composed  of  calcareous 
pieces,  of  which  the  size  and  number  varies  in  different  genera.  Their  long,  slender  rays 
are  supported  internally  on  a  framework  of  central  vertebra-like  pieces ;  they  form  special 
organs  of  locomotion,  independent  of  the  visceral  cavity,  and  numerous  plates  and  spines 
are  regularly  disposed  along  their  sides  to  assist  in  reptation. 

Type.  The  common  Sand-star,  Ophiura  lewturafa,  Lamarck. 

This  order  is  represented  by  one  genus  in  the  Silurian,  and  several  genera  are 
found  in  the  Oolitic,  Cretaceous,  and  Tertiary  rocks,  as  well  as  in  our  present  seas. 

Order  vi.  Blastoidea. — Body  in  the  form  of  an  oval  calyx,  composed  of  solid, 
calcareous  plates,  provided  with  five  inter-ambulacra  and  five  ambulacra,  the  latter  united 
superiorly,  striated  transversely,  and  having  a  deep  furrow  down  the  middle ;  ten  ovarial 
holes,  opening  into  five  at  the  summit,  M-ith  a  central  oral  aperture,  a  short,  slender 
stem,  and  the  body  destitute  of  arnis. 

3 


18  ECHINODERMATA. 

Type.     Peiiirciniles  injlatus,  Sow.     Carboniferous  Limestone. 

Tlie  genera  are  all  extinct,  and  belong  to  the  Palseozoic  rocks.  One  species  appertains 
to  the  Upper  Silurian,  six  to  the  Devonian,  and  twenty-four  are  special  to  the  Car- 
boniferous rocks. 

Order  vii.  Cystoidea. — Body  more  or  less  spherical,  supported  on  a  jointed  stem ; 
the  bursiform  calyx  is  formed  of  close-fitting  polygonal  plates,  varying  in  number  in  the 
different  genera,  and  investing  the  surface  like  a  coat  of  mail,  except  above,  where  there 
are  three  openings,  one  for  the  mouth,  one  for  the  vent,  and  one  with  a  valve  for  the 
reproductive  organs ;  the  fourth  aperture  is  below,  and  continuous  with  the  canal  in 
the  stem.  Some  have  two  or  four  arms,  others  are  armless;  certain  forms  possess  arti- 
culated tentacula  and  curious  comb-like  appendages,  or  pectinated  rhombs,  in  connection 
with  the  plates. 

Type.     Pseudocrinifes  qvadrifasciafiis,  Pearce.     Upper  Silurian. 

This  order  is  extinct.     All  the  genera  are  found  in  the  Silurian  and  Devonian  rocks. 

Order  a'iii.  Crinoidea. — Body  fusiform,  distinct,  formed  of  a  calyx  composed  of  a 
definite  number  of  plates,  provided  with  five  solid  arms,  independent  of  the  visceral 
cavity,  and  adapted  for  prehension;  mouth  and  vent  distinct;  no  retractile  suckers; 
ovaries  at  the  base  of  the  arms  opening  into  special  apertures.  Skeleton  complicated, 
calcareous,  composed  of  thick  plates  closely  articulated  together  ;  their  number 
and  arrangement  are  determinate  in  the  different  families,  the  multiples  of  five  being 
those  which  predominate ;  the  central  plate  of  the  .body  is  supported  on  a  long, 
jointed  column,  that  was  firmly  rooted  to  the  sea-bottom.  The  mouth  is  central,  and 
prominent;  the  vent  is  situated  at  its  side;  the  arms  are  mostly  ramose  and  multi- 
articulate,  and  when  extended  formed  a  net-like  instrument  of  considerable  dimensions. 
The  mouth  is  always  placed  upwards,  and  retained  so  by  the  column  being  jointed  to  the 
central  plate  of  the  calyx.     The  normal  station  of  the  Crinoidea  is   the   reverse  of  the 

ASTEROIDEA  and  ECHINOIDEA. 

Type.     Pentacrinus  Caput-Medusce,  Miller.     From  the  seas  of  the  Antilles. 
Extinct  families  of  Crinoids  have  lived  in  all  seas  from   the  Silurian  upwards,  and 
only  one  or  two  representatives  now  exist. 

From  the  above  analysis  of  the  class  Echinoderjiata,  it  appears  that,  as  the  Sipuncu- 
loidea  and  Hohfhuroidea  are  not  found  in  a  fossil  state,  and  the  Blastoidea  and  Cystoidea 
are  special  to  the  Palaeozoic  rocks,  our  field  of  investigation  in  this  Monograph  is  limited 
to  the  EcHiNOiDEA,  AsTEROiDEA,  OpHiuROiDEA,  and  Crinoidea,  which  we  now  propose 
to  consider  seriatim,  commencing  with  the  Echinoidea. 


ECHINOIDEA.  19 


Order — Echinoidea. 


Tlie  body  is  spheroidal,  oval,  depressed  or  discoidal,  and  enclosed  in  a  calcareous 
test  or  shell,  composed  of  ten  columns  of  large  plates,  Ihe  inter-ambulacral  areas,  and  ten 
columns  of  small  plates,  the  amhulacral  areas,  separated  from  each  other  by  ten  rows  of 
holesj  the  poriferous  zones.  The  external  surface  of  the  plates  is  studded  with  tubercles 
of  various  sizes,  in  the  different  families  ;  to  these  the  spines  are  moveably  articulated  by 
ball-and-socket  joints;  the  spines  are  of  various  forms  and  dimensions,  and  serve  well  to 
characterize  the  species. 

At  the  summit  of  the  test  is  the  apical  disc,  composed  of  five  genital  plates,  perforated 
for  the  passage  of  the  ovarial  and  seminal  canals,  and  five  ocular  plates,  notched  or 
perforated  for  lodging  the  eyes.  There  are  two  great  openings  in  the  test,  one  for  the 
mouth  and  the  other  for  the  vent ;  the  relative  position  of  these  apertures  varies  in  different 
families,  and  forms  an  important  character  in  their  systematic  classification. 

The  mouth  in  some  families  is  armed  with  a  complicated  apparatus  of  jaws  and  teeth, 
in  others  it  is  edentulous.  The  internal  organs  of  digestion  consist  of  a  pharynx, 
oesophagus,  stomach,  and  intestine,  which  winds  round  the  interior  of  the  test,  attached 
thereto  by  a  delicate  mesentery;  its  surface,  as  well  as  the  lining  membrane  of  the 
shell,  is  covered  with  vibratile  cilia ;  these  cause  currents  of  water  to  traverse  the 
interior  of  the  body,  and  perform  an  important  part  in  the  function  of  respiration ; 
the  blood  is  circulated  in  arteries  and  veins,  aided  by  a  central  pulsating  organ  or  heart. 
The  five  ovaries  and  testicles  occupy  the  ambulacral  divisions,  and  open  externally  through 
holes  in  the  genital  plates.  Locomotion  is  performed  by  the  joint  action  of  .the 
tubular  retractile  suckers  and  the  spines.  Many  sea-urchins  attach  themselves  to  rocks 
by  their  tubular  feet,  and  some  bury  themselves  in  limestone  and  sandstone,  or  even 
granitic  rocks,  by  the  abrading  action  of  the  spines. 

The  nervous  system  consists,  according  to  M.  Van  Beneden,  of  a  circular  cord,  which 
surrounds  the  entrance  to  the  digestive  organs,  and  sends  branches  into  the  divisions  of 
the  body.  Professor  Agassiz,  and  the  late  Professor  Edward  Eorbes,  regarded  the  organs 
situated  in  the  ocular  plates  as  eyes,  but  M.  Dujardin^  denies  them  even  a  nervous 
system.  In  the  absence  of  more  direct  anatomical  evidence  on  the  point,  the  following 
observation,  related  by  M.  Alcide  d'Orbigny,"  has  an  important  bearing  on  the  question, 
and  supports  it  affirmatively : 

Captain  Ferdinand  de  Cande,  who  commanded  the  '  Clcopatre'  in  the  Chinese  seas, 
told  M.  d'Orbigny  that  he  had  captured,  on  the  coast  of  that  region,  an  urchin  with  long 
spines,  probably  a  Diadtma,  which  he  examined  in  a  vessel  of  water,  "I  hastened  to 

1  Lamarck,  '  Animaux  sans  Vertebres,'  2nd  ed.,  torn,  iii,  p.  200. 

2  '  Paleontologie  Fran9aise,  Terrain  Cretace,'  torn.  y\,  p.  12. 


20  ECHINOIDEA. 

seize  it,"  he  observed,  "  when  it  instantly  turned  all  its  spines  in  the  direction  of  my 
hand,  as  if  to  defend  itself. 

"  Surprised  at  this  manoeuvre,  I  made  an  attempt  to  seize  it  on  the  other  side,  when 
immediately  the  spines  were  directed  towards"  me. 

"  I  thought  from  this  that  the  urchin  saw  me,  and  that  the  motion  of  the  spines  was 
intended  as  an  act  of  self-defence ;  but,  to  prove  whether  the  movement  of  the  animal 
was  produced  by  my  approach,  or  merely  by  the  agitation  of  the  water,  I  repeated  the 
experiment  very  slowh^,  and  even  over  the  water  with  a  stick.  The  urchin,  whether  in 
the  water  or  out  of  it,  having  always  directed  its  defensive  spines  towards  the  object  which 
approached  it.  From  these  observations  I  arrived  at  the  conclusion  that  these  urchins 
see,  and  that  their  spines  serve  them  as  defensive  instruments." 

It  is  worthy  of  remark,  that  Captain  Cande,  at  the  time  he  watched  this  urchin,  was 
ignorant  of  the  anatomical  fact  that  eyes  had  been  detected  in  the  Echinidae,  and  his 
inference  was  the  conclusion  drawn  from  carefully  made  observations. 

The  calcareous  test  of  the  Echinoidea  is  the  only  part  of  the  structure  of  these  animals 
preserved  in  a  fossil  state.  It  has  hitherto  failed  to  attract  that  amount  of  atten- 
tion from  the  palaeontologist  which  the  importance  of  its  study  demands  ;  although  in  a 
stratigraphical  point  of  view  this  skeleton  is  not  inferior  to  that  of  any  other  class  of  the 
Animal  Kingdom.  The  fact  seems  to  have  been  almost  entirely  overlooked  by  paltcon- 
tologists,  that  most  of  the  generic  characters  of  the  different  groups  of  Echinidce  are  more 
indelibly  impressed  on  the  separate  pieces  of  their  test  than  in  the  skeletons  of  any  other 
class  of  the  Invertebrata. 

Unlike  the  shells  of  the  Mollusca,  the  test  of  the  Echinoidea  constitutes  an  internal  and 
integral  portion  of  the  animal,  being  secreted  by,  and  enclosed  within,  organized  mem- 
branes, it  participates  in  the  life  of  the  organism,  and  certain  parts  of  the  skeleton  are 
intimately  connected  with  the  organs  of  digestion,  respiration,  and  generation,  as  well  as 
with  those  of  vision  and  locomotion. 

As  it  is  intended  to  give  an  analysis  of  the  test  of  the  Echinoidea,  M'itli  anatomical 
details  of  the  structure  of  the  skeleton  in  the  Echinodermata  in  general,  in  the  General 
Introduction  to  these  Monographs,  it  is  at  present  unnecessary  to  enter  minutely  into  the 
subject ;  but,  as  many  of  our  readers  are  doubtless  unacquainted  with  the  terminology 
employed  in  the  description  of  the  test,  and  the  characters  on  which  a  diagnosis  of  the 
species  is  made,  it  is  desirable  now  to  preface  our  description  with  brief  explanations  of 
the  same,  illustrating  the  terminology  by  a  reference  to  the  plates  for  accurate  figures  of 
different  parts  of  the  test,  and  magnified  details  of  the  anatomical  characters  thereof.^ 

'  In  connection  with  the  physiology  of  the  Echinodermata,  the  following  discovery,  made  by  Dr. 
WalHch,  i.s  most  important : 

"Thirteen  living  star-fishes,  differing  in  no  important  particular  from  a  species  common  on  our  own 
and  most  northern  coasts,  were  brought  up  from  a  depth  of  12G0  fathoms,  or  very  nearly  a  mile  and  a 
half,  at  a  point  midway  between  the  southern  extremity  of  Greenland  and  Ttocknll,  and  250  miles  distant 
from  ih.e  nearest  land.     Tiiesc  star-fishes,  however,  cnnnot  be  said  to  have  been  captured  by  the  sounding- 


TERMINOLOGY.  21 

TERT^IINOLOGY, 

Or  a  descriptive  analysis  of  the  comjioiici)f  elements  of  the  test  of  the  Echinoidea. 

The  test  of  the  Echinoidea  is  composed  of  tlie  following  parts  : 

a.  Five  ambulacral  areas. 

b.  Five  inter-ambulacral  areas. 

c.  Ten  poriferous  zones. 

d.  Vent- opening  and  anal  plates. 

e.  Month-opening,  peristome,  buccal  membrane  and  plates. 
/.  Five  jaws  when  organs  of  mastication  exist. 

(/.  Tubercles  of  various  sizes,  developed  from  the  outer  surface  of  the  plates. 
//.  Spines  of  different  forms  and  dimensions,  jointed  with  the  tubercles. 

These  are  the  essential  parts  to  be  known  ;  others,  of  secondar}^  importance,  will  be 
described  in  their  proper  place  in  the  Monograph. 

The  hodt/of  the  Echinoidea  is  divisible  into  three  parts  : — 1st.  The  calcareous  envelope, 
or  skeleton,  which  has  a  globular,  circular,  oval,  pentagonal,  hemispherical,  conoidal,  or 
discoidal  form,  and  is  composed  of  a  framework  of  hexagonal,  pentagonal,  or  polygonal 
calcareous  plates.  This  testaceous  box  is  called  the  test;  it  is  the/o/w,  the  test,  of 
Agassiz ;  the  (jeneral  form,  the  test,  of  Desmoulins  ;  h  coquitle,  d'Orbigny. 

machine,  for  they  came  up  adhering  by  their  spine-covered  arms  to  the  last  fifty  fathoms  of  the  sounding- 
line,  not  as  voluntary  exiles  from  below,  but  owing  to  their  having  coiled  themselves  around  a  material 
from  which  they  found  it  impossible  afterwards  to  disengage  themselves.  Now,  apart  from  all  other 
evidence,  the  facts  in  connection  with  this  particular  sounding  were  sufficient  to  indicate  that  the  star- 
fishes had  been  raised  from  the  sea-bed  itself,  and  had  not  grasped  the  line  whilst  floating  in  some  stratum 
of  water  intermediate  between  it  and  the  surface.  But,  by  a  singular  piece  of  good  fortune,  the  question 
as  to  their  last  resting-place  admitted  of  definite  determination  on  evidence  that  they  bore  along  with 
them.  To  comprehend  the  value  of  this,  it  is  necessary  to  mention  that,  by  means  of  a  separate  observa- 
tion taken  upon  the  same  spot,  the  bottom  was  found  to  consist  almost  entirely  of  the  minute  shell-covered 
organisms  (Foraminifera)  already  referred  to  ;  and  faking  into  consideration  the  fact  that  many  of  the  shells 
were  completely  filled  with  the  gelatinous  substance  of  which  their  bodies  are  composed,  and,  lastly,  the  fresh 
appearance  of  this  substance,  the  probability  is  very  great  that  they,  in  common  with  the  star-fishes,  had 
lived  and  multiplied  at  the  bottom.  But  the  only  circumstance  which  ought  to  be  accepted  as  direct  proof 
of  their  vitality,  namely,  motion  after  reaching  the  surface,  was  wanting  ;  as  it  well  might  be,  since 
the  passage  through  the  vertical  mile  and  a  half  of  water  occupied  nearly  an  hour,  and  the  change  of 
conditions  to  which  the  creatures  became  subjected  during  that  period  must  necessarily  have  been  very 
great.  Nevertheless,  the  chain  of  circumstantial  evidence  was  rendered  complete ;  for,  on  examining  the 
stomachs  of  the  star-fishes,  they  were  found  to  contain  the  minute  shelled  creatures  in  abundance,  thus 
clearly  establishing  the  fact  of  the  star-fishes  having  attached  themselves  to  the  sounding-line  whilst  it 
rested  on  the  bottom,  and  adding  the  strongest  confirmation  to  the  view  that  the  minute  creatures  referred 
to  were  brought  up  from  their  natural  habitation."  (Dr.  Wallich,  "  On  the  Deep-Sea-Bed  of  the  Atlantic,  and 
its  Inhabitants;"  '  Quarterly  Journal  of  Science,'  No.  1,  p.  40.) 


22  ECHINOIDEA. 

2nd.  The  visceral  cavity,  containing  the  organs  of  digestion,  respiration,  circulation, 
and  generation,  is  formed  entirely  by  the  interior  of  the  test. 

3rd.  The  external  surface  of  the  test  is  covered  with  spines,  which  are  moveal^ly 
articulated,  with  the  tubercles  seen  on  the  surface. 

The  normal  position  of  the  hody. — In  describing  the  different  parts  of  the  test  of  the 
Echinoidea,  it  is  assumed  that  an  urchin,  the  common  purple  heart-urchin,  Sjjatangus 
purpureus,  Miiller,^  for  example,  is  placed  before  the  observer.  The  side  with  the  single 
ambulacrum  lodged  in  the  anteal  sulcus,  and  the  mouth  in  that  third  of  the  base,  is  the 
anterior  ret/ion.  The  side  having  the  single  inter-ambulacrum  in  the  middle  and  the  vent- 
opening  in  the  upper  part  of  the  border  is  the  posterior  region.  The  four  other  ambu- 
lacra are  disposed  in  pairs,  and  correspond  to  the  right  and  left  sides  of  the  observer's 
body ;  there  is,  therefore,  a  right  antero-lateral  and  a  right  postero-lateral,  a  left  antero- 
lateral and  left  postero-lateral,  ambulacral  area.  The  four  other  inter-ambulacra,  besides 
the  single  one  in  which  the  vent  is  situated,  are  likewise  disposed  in  pairs,  two  of 
these,  with  the  single  ambulacrum,  forming  the  anterior  part,  the  other  pair,  with  the 
pairs  of  ambulacra,  the  sides,  and  the  single  inter-ambulacrum  the  posterior  part  of 
the  test. 

All  Echinoidea3  have  the  mouth  situated  at  the  under  side  of  the  body ;  the  surface  in 
which  the  opening  is  placed  is  the  base,  that  region  of  the  test  opposite  the  base  is  the 
up2)er  or  dorsal  surface. 

The  most  convex  part  of  the  margin,  border,  or  sides,  between  the  base  and  upper 
surface,  is  the  circumference,  or  ambitus  of  some  authors ;  it  is  round,  flat,  convex,  angular, 
or  carinated,  according  to  the  general  form  and  thickness  of  the  test. 

The  length  or  antero-posterior  diameter  is  the  distance  between  the  anterior  and 
posterior  regions,  and  corresponds  to  the  middle  line  of  the  body. 

The  breadth  or  transverse  diameter  is  the  distance  between  the  greatest  lateral 
convexity  of  the  circumference  in  the  direction  of  a  line  cutting  the  line  of  length  at 
right  angles. 

The  height  is  the  distance  between  the  most  convex  part  of  the  upper  surface  and  the 
plane  on  which  the  base  of  the  test  rests.  The  apical  disc  is  generally  situated  at  the 
vertex,  but  it  is  not  always  so ;  the  height  has  always  reference  to  the  highest  point  of  the 
test,  quite  irrespective  of  any  other  consideration.  The  test  has  invariably  two  openings, 
one  for  the  mouth,  the  other  for  the  vent. 

The  mouth-opening  is  always  situated  at  the  under  surface ;  to  its  circumference  is 
attached  the  buccal  membrane,  and  through  the  central  aperture  thereof  protrudes  the 
five  jaws  (PL  V,  fig.  1 ;  PI.  VII,  fig.  1) ;  when  they  exist,  the  buccal,  like  the  anal  mem- 
brane in  many  families,  is  clothed  with  numerous  small  plates. 

In  the  Cidaris,  Rabdocidaris,  Goniocidaris,  Diplocidaris,  and  probably  in  all  other 

'  Tlie  common  Chalk-urchin  Miraster  cor-anginum,  Klein,  -will  answer  equally  well. 


TERMINOLOGY.  23 

Cidaridce,  the  mouth-opening  is  central,  circular,  or  slightly  pentagonal  (PI.  IV,  fig.  16) ; 
but  in  Hcmicidaris,  Pseudodiadema,  Ilemipcduia,  Pedina,  Echinus,  and  other  Echi?iideB,  the 
mouth-opening  is  more  or  less  decagonal,  its  margin  being  divided  by  notches  {eniaiUes) 
into  ten  lobes ;  the  lobes,  in  general,  are  unequal  in  size,  those  corresponding  to  the 
base  of  the  ambulacra  being  the  largest ;  they  are  called  the  amhilacral  lobes ;  corre- 
sponding to  the  base  of  the  inter-ambulacra  are  the  inter-ambulacral  lobes.  The  margin  of 
the  mouth-opening  is  called  the  j-jc^mYo^wc,  to  it  the  buccal  membrane  which  closes  the 
base  of  the  test  is  attached. 

The  mouth-openinf/  is  central  and  armed  with  jaws  in  the  Cidarid.e,  Echinid/E, 
Salenid^,  Gai.eritid^,  and  Clypeasterid^.  It  is  more  or  less  excentral  and  edentulous 
in  the  Echinonid^,  Collyritid^,  EchinolampidjE,  EchinocorydjE,  and  Spatangid^; 
in  them  it  is  round,  oval,  or  pentagonal;  sometimes  its  margin  is  ring-like,  or  surrounded 
by  five  prominent  lobes ;  in  others  it  is  distinctly  bilabiate. 

The  ve)it,  or  anal  oj)ening,  is  always  in  the  upper  surface,  in  the  centre  of  the  genital 
and  ocular  plates,  directly  opposite  to  the  mouth,  and  is  either  central  or  subcentral  in 
the  CiDARiDiE,  EcHiNiDiE,  and  Salenid^  (PI.  VI,  fig.  1).  In  other  families  its  position 
varies  much ;  sometimes  it  opens  on  the  upper  surface,  as  in  some  Galeritid^  and 
Cassidtjlid^.  Sometimes  it  opens  on  the  margin  or  is  siqyra-marglnal,  marginal  or 
infra-marff'uial;  often  it  opens  at  the  base  between  the  mouth  and  the  border.  During  the 
life  of  the  animal  this  opening  is  closed  by  an  anal  membrane  and  a  series  of  small  angular 
anal  plates  ;  their  number  and  disposition  varies  in  the  different  genera.  The  anal  plates 
are  seldom  preserved  in  fossil  species,  and  the  term  anal  opening  is  given  to  all  that  part 
of  the  test  occupied  by  them  and  the  vent.  PI.  VI,  fig.  1  a,  is  a  magnificent  specimen  of 
Cidaris  scejjlrifera,  Mant.,  belonging  to  the  British  Museum,  in  which  the  anal  plates  are 
finely  preserved  in  situ. 

The  Ambulacral  and  Inter-ambidacral  Areas. 

The  test  is  composed,  1st,  of  twenty  columns  of  calcareous  plates  of  different  sizes,  the 
plaquettes,  Tdfekhen,  Assulce  of  authors ;  they  are  pentagonal  in  form,  and  united  by 
harmonial  sutures  to  form  rays,  which  proceed  from  the  mouth,  where  they  have  their 
greatest  breadth,  to  the  apical  disc,  where  they  are  narrowest.  2nd.  Of  a  series  of  hexagonal 
or  polygonal  plates,  forming  a  disc,  which  occupies  the  upper  surface  of  the  test.  3rd.  Of 
ten  rows  of  small  plates,  notched  on  their  margins  to  form  holes;  these  form  the 
poriferous  zones.  4th.  Of  moveable  spines,  that  are  jointed  with  eminences  on  the  outer 
Surface  of  the  columnar  plates. 

The  ambulacral  plates  form  two  narrow  columns,  which  are  bounded  by  two  poriferous 
zones.  The  space  thus  circumscribed  is  the  ambulacral  area.  There  are  five  of  these  areas 
in  the  test  of  the  Echinoidea.  In  the  Cidarid^  the  ambulacral  areas  are  very  narrow, 
and  support  only  granules  (PI.  VI,  fig.  1,  a,  b,  c,  d).     In  the  Echinid^,  they  are  much 


24  ECHINOIDEA. 

wider,  and  liave  large  tubercles  on  their  surface.  The  comparative  width  of  the  ambulacra 
as  compared  with  the  inter-ambulacra  has  led  some  authors  ^  to  divide  the  family  Cidnrldcc, 
including  therein  the  EchinUhe,  into  two  tribes,  the  Angustistell.^,  or  Cidaridse  with 
narrow  ambulacra,  and  the  Latistell^e,  or  Cidarida^  with  broad  ambulacra.  These  two 
tribes  nearly  represent  our  two  families  ;  the  Cidarid.e  are  equal  to  the  Angustistell.e, 
and  the  Echinid^  are  nearly  equal  to  the  Latistell^e. 

One  of  the  ambulacral  areas  is  single,  and  always  represents  the  anterior  region  in  the 
spheroidal  Ecldnkla:  and  Bulcnidce.  'Jliis  is  detected  by  its  relation  to  the  apical  disc, 
as  the  right  antero-lateral  plate  always  carries  the  madreporiform  body;  in  the  oval, 
pentagonal,  or  elongated  forms,  its  position  and  relation  to  the  mouth  renders  it  unmis- 
takeable.     The  four  other  ambulacra  are  disposed  in  pairs. 

The  iuter-amhvJacrul  jiiates  form  two  broad  columns,  composing  the  inter-ambulacral 
areas ;  of  these,  like  the  ambulacral,  there  are  five,  which  alternate  with  them  in  the  archi- 
tecture of  the  test.  The  poriferous  zones  form  the  line  of  demarcation  between  these  two 
classes  of  columnar  plates.  The  plates  are  all  pentagonal,  and  many  times  larger  than 
the  ambulacral ;  they  carry  on  their  surface  the  large  primary  tubercles.  Of  the  five  inter- 
ambulacral  areas,  one  is  single  and  posterior,  and  in  all  the  Echinoidese  which  have  the  anal 
opening  external  to  the  apical  disc  it  is  in  the  single  inter-ambulacrum  that  the  vent  ter- 
minates. The  other  four  inter-ambulacra  are  disposed  in  pairs,  and  form  the  greater 
part  of  the  anterior  and  lateral  parts  of  the  test ;  they  are  the  anterior  pairs  and  poitcrior 
pairs,  respectively,  to  distinguish  them  from  the  odd  area,  which  is  the  siri^le  inter- 
ambulacrum. 

PI.  VI,  fig.  1,  shows  the  form  and  structure  of  the  inter-ambulacra  in  the  CidaridcB. 

In  the  Cidaridce  the  inter-ambulacral  areas  have  only  two  rows  of  primary  tubercles ; 
but  in  many  of  the  Echinida'  there  are  four,  six,  eight,  or  ten  rows  of  primary  tubercles 
in  these  areas. 

Tlie  Poriferous  Zones. 

Tlie  poriferous  zones  are  situated  on  each  side  of  the  ambulacral  areas  (PI.  VI,  fig.  1) ; 
they  are  composed  of  a  very  great  number  of  small  pieces,  articulated  together  in  such  a 
manner  as  to  form  a  series  of  holes.  The  corresponding  edges  of  the  plates  remaining 
rnicalcified,  at  certain  definite  intervals  produce  foramina,  which  are  destined  for  the 
passage  of  retractile  tubular  suckers.  The  form  and  structure  of  the  poriferous  zones  form 
a  good  generic  character.  As  there  are  two  poriferous  zones  bordering  each  ambulacral 
area,  it  follows  that  there  are  ten  zones.  Some  authors  give  the  collective  name  ambulacra 
to  the  zones  and  the  area;  but  for  obvious  reasons,  I  consider  them  distinct  sections  of 
the  test,  and  treat  them  as  such. 

1  Albin  Gras,  'Description  dcs  Oursiiis  Fossiles  du  depaiteuieut  de  I'lsere,'  p.  20.     E.  Dt'sor,  'Synopsis 
ties  Ecliinides  Fossiles,'  p.  2C. 


ter:minology.  25 

The  pores  are  round,  oblong,  or  elongated ;  the  pores  forming  a  pair  may  be  equal  or 
unequal ;  in  relation  to  each  other,  they  raay  be  transverse  or  oblique,  contiguous  or 
remote,  and  when  united  by  a  transverse  sulcus  they  are  said  to  be  conjugate. 

The  pores  are  differently  arranged  in  the  zones  in  the  different  families  :  when  they  are 
disposed  in  single  pairs,  they  are  said  to  be  unigeminal  (PI.  VI,  fig.  1,  d);  when  in  double 
pairs,  bigeminal ;  when  in  triple  oblique  pairs,  trigeminal ;  and  when  grouped  in  a  greatei' 
number,  as  in  many  living  species  of  the  genus  Echinus,  they  are  polygeminal . 

When  the  zones  extend  in  a  straight  uninterrupted  line  from  the  mouth  to  the  apical 
disc,  they  are  said  to  be  simjile,  as  in  the  Cidarida,  Echiiiidte,  Salenida,  Galerilida, 
EchinonidcB ;  when  the  zones,  after  parting  from  the  apical  disc,  expand,  and  again 
contract,  thereby  forming  a  leaf-like  figure  on  the  upper  surface  of  the  test,  they  are  said 
to  be  pefaloidal,  as  in  the  ClypeasteridcB ;  wlien  the  petal  is  not  so  complete,  as  in  the 
CassidulidcB,  it  is  subpetaloidal.  The  zones  are  complete  when  they  extend  without  inter- 
ruption from  the  mouth  to  the  disc ;  they  are  interrupted  when  they  terminate  on  the 
upper  surface,  and  reappear  again  at  the  base  near  the  mouth  ;  they  are  limited  when 
they  form  only  a  star  on  the  dorsal  surface.  These  terms  represent  generic  characters 
of  greater  or  less  value,  and  require  to  be  carefully  noted  in  the  description  of  the 
species. 


17ie  Apical  or  Genital  Disc. 

The  apical  disc  occupies  the  centre  of  the  summit  of  the  test,  and  is  composed  in 
most  genera  of  ten  plates,  namely,  five  genital  plates  and  five  ocular  plates  (PI.  VI, 
fig.  1,  «).  In  the  Salenidce  there  is  one  or  more  additional  plates  introduced.  The  five 
genital  or  oviductal  plates  correspond  to  the  sunnnits  of  the  inter-ambulacral  areas  ;  two 
plates  form  an  antero-lateral  pair,  two  a  postero-lateral  pair,  and  the  single  plate  is 
placed  behind.  On  the  right  antero-lateral  genital  plate  (PI.  VI,  fig.  1,  a)  is  a  spongy, 
prominent  mass,  called  the  madreporiform  body ;  the  plate  supporting  this  body  was 
supposed  by  Agassiz  and  Desor  always  to  represent  the  posterior  part  of  the  test,  but  I 
have  shown  that  it  is  invariably  placed  on  the  right  antero-lateral  plate. 

The  ocular  plates  are  at  the  summit  of  the  ambulacral  areas ;  they  are  small,  heart- 
shaped  bodies  (PI.  VIII,  fig.  4,  b),  wedged  into  the  angles  of  the  genital  plates  around 
the  circumference  of  the  disc. 

The  suranal  plates  are  found  only  in  the  Salunid^;  they  consist  of  one  or  many 
elements  placed  in  the  centre  of  the  genital  circle,  and  always  before  the  anal 
opening. 

The  anal  plates  (PI.  VIII,  fig.  4,  b),  are  very  small  bodies,  and  variable  as  to  number ; 
they  clothe  the  membrane  of  the  anal  opening,  and  are  well  seen  in  recent  urchins ;  but 

4 


26  ECHINOIDEA. 

are  seldom  preserved  in  fossil  species ;  they  are  admirably  shown,  however,  in  the  fine 
specimen  of  Cidaris  subvesiculosa  (PI.  VIII,  fig.  4),  from  the  collection  of  our  kind 
friend,  Dr.  Bowerbank,  F.R.S. 


The   Tnherchs. 

The  plates  composing  the  test  of  the  Cidaridx,  Echimdce,  and  Salenidce,  have 
large  tubercles  developed  on  their  surface;  they  are  divided  mia primary  tubercles,  semi- 
tubercles,  secondary  tubercles,  minute  tubercles,  granules,  and  miliary  granulation.  In  the 
other  families  the  tubercles  are  smaller,  more  numerous,  and  less  complicated. 

The  primary  tubercles  form  two  rows  in  the  inter-ambulacral  areas  of  the  Cidaridce, 
(PI.  I  and  II),  and  four,  six,  eight,  ten,  or  twelve  rows  in  many  Echinida. 

The  semi-tubercles  are  found  at  the  base  of  the  ambulacral  areas  of  the  genus  Hemi- 
cidaris.  In  a  section  of  the  genus  Hemipedina  they  likewise  are  found  at  the  base  of  the 
ambulacra. 

The  secondary  tubercles  are  found  in  many  of  the  EcTiinidee,  ranged,  in  general,  on  the 
ambulacral  side  of  the  primary  tubercles.  They  are  found  likewise  on  the  centro-sutural 
side  of  the  primary  rows  of  many  Pseudodiademu,  Pedina,  Hemipedina,  and  Echinus. 

The  minute  tubercles  are  the  small  tubercles  found  on  the  margins  of  the  ambulacral 
areas  of  the  genus  Cidaris  (PI.  VIII,  fig.  1) ;  and  they  sometimes  fill  up  spaces  at  the  base 
of  the  inter-ambulacral  areas.  In  sonae  Pseudodiademata  they  are  raised  on  Tittle 
eminences,  and  perforated  like  the  secondary  and  primary  tubercles.  In  this  respect 
they  are  distinguished  from  the  granules. 

The  granules  are  small,  round,  hemispherical  elevations,  scattered  more  or  less  regularly 
over  diftei-ent  parts  of  the  plates  of  the  test.  In  some  species  of  the  genus  Cidaris  they 
are  arranged  in  rows  in  the  centre  of  the  ambulacral  areas,  or  form  circles  around  the 
circumference  of  the  areolas  of  the  primary  tubercles  (PL  VIII). 

The  miliary  granulation  is  formed  by  a  number  of  small  granules  closely  set  together 
in  the  centre  of  the  ambulacra,  or  on  the  inter-tubercular  surface  of  the  large  plates 
composing  the  inter-ambulacra  (PI.  VIII,  fig.  1). 

The  priniai'y  tubercles  of  the  genera  Cidaris,  Hemicidaris,  Psevdodiadema, 
Hemipedina,  Pedina,  &c.,  consist  of  the  following  parts  : 

The  hemispherical  tubercle,  or  mamelon,  is  sometimes  perforated  in  the  centre,  some- 
times imperforate,  as  in  many  Echinidce  (PI.  VII,  fig.  3  r). 

Tlie  loss,  or  mauimillary  eminence,  is  tlie  conical  prominence  on  the  surface  of  the 
tubercular  plate ;  its  summit  supports  the  tubercle,  and  the  margin  thereof  is  crenulated 
in  Hemicidaris  and  Pseudodiadema,  and  smooth  in  Hemipedina  and  Pedina. 

These  characters  are  important  for  generic  distinctions. 


TERMINOLOGY.  27 

The  areola,  or  scrobicule  (PI.  VI,  fig.  1,  d),  is  the  round,  oval,  or  eUiptical,  smooth, 
excavated  space  which  surrounds  the  base  of  the  boss.  This  space  is  sometimes  narrow, 
and  its  margin  elevated  into  a  ridge,  that  completely  encircles  it,  when  the  scrobicule 
or  areolar  circle  is  said  to  be  complete ;  if  the  upper  and  under  sides  of  the  circle  are 
wanting,  it  is  incomplete,  and  the  areolas  are  then  said  to  be  confluent. 

The  row  of  granules  encircling  the  areolas  is  called  the  areolar  or  scrobicular 
circle. 

The  miliary  zone  is  the  space  comprised  between  two  ranges  of  primary  tubercles, 
it  is  in  general  covered  with  a  close-set  granulation  ;  Avhen  destitute  of  miliary 
granules,  it  is  said  to  be  naked  ;  the  ambulacral  and  inter-ambulacral  miliary  zones 
occupy  these  different  regions  of  the  shell. 

When  the  granules  are  microscopic,  and  closely  clustered  together  within  certain 
narrow,  circumscribed  bands,  or  fascioles,  intersecting  the  general  tubercular  surface,  and 
occupying  fixed  positions  on  the  test,  they  are  ceiWed  fasciolar. 

Fascioles  are  only  found  in  two  families,  in  one  genus  of  the  Echinocoridee,  and  in 
almost  all  the  genera  of  the  Spatanc/idce.  The  form,  width,  structure,  and  position  of  these 
bands  must  be  carefully  noted,  as  they  afford  important  characters,  both  positive  and 
negative,  for  the  diagnosis  of  the  genera. 

When  a  fascicle  surrounds  the  circumference  of  all  the  petaloidal  portions  of  the  am- 
bulacral areas,  it  1%  peripetalous ;  if  it  encircles  the  single  ambulacrum  alone,  it  is  internal ; 
when  it  extends  along  the  flanks,  it  is  lateral ;  if  it  passes  in  whole,  or  in  part,  along 
the  circumference,  it  is  marginal ;  and  when  it  surrounds  the  base  of  the  single  inter- 
ambulacrura,  it  is  suhanal.  Sometimes  there  is  only  one.,  sometimes  there  are  two  or 
three,  of  these  fascioles  in  different  genera. 

Each  family  has  a  special  arrangement  of  the  tubercles,  granules,  and  fascioles ;  a 
detailed  account  of  these  will  be  found  in  the  general  outline  of  the  structural  characters 
prefixed  to  the  description  of  each  natural  group. 

The  sutural  impressions  are  the  lines  along  which  the  plates  are  united  together  ;  some- 
times they  are  mere  lines ;  or  the  impressions  amount  to  excavations  out  of  the  borders 
of  the  plates,  and  give  rise  to  cavities  therein,  as  in  the  genus  Temnopleurus. 

The  angular  or  sutural  pores  are  small  impressions,  situated  in  some  genera  at  the 
angles  of  the  plates,  upon  the  median  line  of  the  miliary  zones. 


The  external  Appendages  of  the  Test. 

The  spines,  or  radioles,  as  they  were  called  by  Plott,  Lang,  and  other  old  authors,  are  the 
calcareous  appendages  that  are  moveably  articulated  to  the  tubercles  of  the  test ;  they 
present  numerous  modifications  as  to  size,  form,  and  sculpture,  which  are  all  intimately 


28  ECHIXOIDEA. 

connected  with  specific  characters  ;  some  are  shorter  elongated,  flattened,  cylindrical,  fusi- 
form, or  subulate  ;  others  are  compressed,  spatuliforra,  or  triangular  ;  others,  on  the  contrary, 
are  expanded,  pyriform,  or  claviform.  The  surface  of  the  spines  is  smooth  or  striated  with 
fine  or  coarse  longitudinal  lines ;  some  have  verticillate  processes  at  regular  intervals,  others 
have  asperities,  prickles,  or  granules,  disposed  with  more  or  less  regularity  over  the  surface. 
The  different  parts  of  the  spine  have  received  the  following  names  : 

'J'he  articular  cavity,  or  acetabulum,  is  the  socket  by  which  the  spine  articulates  with  the 
tubercle  ;  its  margin  is  smooth  orcrenulated,  according  as  the  summit  of  the  boss  is  smooth 
or  crenulated  (PI.  VI  and  VII) ;  in  all  the  genera  with  perforated  tubercles  there  is 
a  corresponding  pit  in  the  socket  of  the  spine,  for  the  attachment  of  the  round  ligament 
which  passes  from  the  tubercle  to  the  spine. 

The  head  is  that  part  of  the  spine  containing  the  articulating  cavity,  and  is  united  to 
the  stem  near  the  necl^  (PI.  VII,  fig.  4). 

The  milled  riiiff  surrounds  the  head  ;  it  is  a  prominent  ridge,  more  or  less  deeply 
crenulated,  around  which  the  muscular  fibres  that  move  the  spine  are  firmly  attached. 

The  neck  is  the  smooth  space  between  the  line  of  jiuiction  above  the  milled  ring  and 
the  rugose  body  of  the  spine  (PI.  VII  and  VIII).  In  long,  slender,  tapering  spines,  it  is 
often  finely  striated  with  longitudinal  lines,  and  cannot  be  distinguished  from  the  body  into 
wliich  it  jiasses. 

The  stem  or  boch/  of  the  ftpiiie  is  the  part  that  exhibits  the  greatest  variety  of  forms, 
smooth  and  muricated  varieties  are  figured  in  PI.  I,  II,  IV. 

The  organs  of  mastication  forming  "  the  lantern  of  Aristotle  "  are  rarely  preserved  in 
fossil  species;  they  consist  of  five  jaws,  each  carrying  a  long  tooth  (PI.  V  and  VII).  As 
these  parts  form  a  complicated  mechanism,  their  analysis  and  description  wall  be  given  at 
length  in  the  anatomical  part  of  the  introduction. 


On  tite  relative  value  of  the  e.rternal  organs  in  the  classification  of  the  Echinoidea. 

The  mouth  is  always  basal,  central,  subcenti'al,  or  excentral,  but  the  excentricity  is 
invariably  towards  the  anterior  border.  This  opening  does  not,  therefore,  afford  a  charac- 
ter of  primary  importance,  although,  in  connection  with  others,  it  is  valuable  in  the  definition 
of  families.     The  month  is  .«ometimes  armed  with  jaws,  but  it  is  oftener  edentulous. 

The  position  of  the  anal  opening  affords  a  character  of  primary  importance.  In  one  great 
section  the  vent  opens  icithin  the  centre  of  the  apical  disc,  surrounded  by  the  genital  and 
ocular  plates.  The  relation,  therefore,  of  the  digestive  organs  to  those  of  generation  and 
\ision,  is  an  important  primary  character  for  the  zoologist.  In  another  section  the  vent 
opening  is  without  the  apical  disc,  and  is  more  or  less  external  to,  and  at  a  greater  or  less 
distance  from,  the  genital  and  ocular  plates.  The  physiological  importance  of  the  external 
relation  of  the  organs  of  digestion,  generation,  and  vision,  to  each  other,  imparts  great 


CLASSIFICATION.  29 


A 


alue  to  the  position  of  the  anal  opening ;  and  hence  it  forms  the  basis  of  the  subdivision 
of  this  order  into  two  sections,  which  are  thus  defined : 


EcJdnoidea  endocydica. 

A.  Test  circular,  spheroidal,  more  or  less  depressed,  rarely  oblong ;  mouth  in  the  centre 
of  the  base.  Vent  in  the  centre  of  the  upper  surface,  directly  opposite  to  the 
mouth,  surrounded  by  five  perforated  genital  plates,  and  having  external  to  them 
five  ocular  plates.  Mouth  always  armed  with  five  powerful  calcareous  jaws,  formed 
of  many  elements,  disposed  in  a  vertical  direction. 


Echinoidea  exocyclica. 

B.  Test  sometimes  circular  and  hemispherical ;  ofteuer  oblong,  pentagonal,  depressed, 
clypeiforra,  or  discoidal ;  mouth  central  or  ex-central.  Vent  external  to  the  circle 
of  genital  and  ocular  plates,  never  opposite  the  month,  and  situated  in  different 
positions  in  relation  to  that  opening  :  four  of  the  genital  plates  are  generally 
perforated.  The  mouth  is  sometimes  armed  with  five  jaws,  oftener  it  is 
edentulous.  The  elements  of  the  lantern  are  disposed  in  a  more  or  less  horizontal 
.direction. 

The  structure  of  the  ambulacral  areas,  and  poriferous  zones,  afford  good  characters 
of  secondary  importance  for  grouping  the  genera  into  natural  families,  especially  when 
taken  in  connection  with  the  position  of  the  vent,  which  varies  in  its  relation  to  that  of 
the  mouth-opening  in  different  families. 

The  form,  number,  and  arrangement  of  the  tubercles,  and  the  spines  that  are  jointed 
with  them  ;  the  miliary  granulation  ;  the  bands  of  microscopic  granules  forming  the  fas- 
cioles,  having  permanent  positions  on  the  test ;  also  the  size  and  number  of  the 
elements  of  the  apical  disc,  and  the  position  of  the  vent,  afford  collectively  good  characters 
for  defining  the  genera. 

The  minute  details  of  the  structure  of  the  plates ;  the  form,  size,  and  number  of  the 
tubercles  on  each  of  them  ;  the  arrangement  of  the  pores,  their  proximity  or  remoteness 
from  each  other  in  the  zones ;  the  general  outline  of  the  test,  which  has  only  certain 
limits  of  variation  ;  the  form  of  the  areolas;  the  presence,  absence,  size,  and  distribution, 
of  the  granules  forming  the  scrobicular  circle ;  the  completeness  or  incompleteness  of  the 
same  ;  the  length  of  the  spines,  their  form  and  sculpture,  are  points  affording  good  specific 
characters,  as  they  are  persistent  details  that  are  developed  on  every  considerable  fragment 
of  the  test  and  spines  of  the  Echinoideae. 


30 


ECHINOIDEA. 


Taking  these  general  principles  for  my  guidance,  I  subdivide  the  Echinoidea  into 


the  followins:  thirteen  natural  families 


Order— ECamOlDE  A.     { 


Echinoidea  endocyclica. 

Vent  within  the  genital  plates, 
always  opposite  the  mouth. 


Echinoidea  exocyclica. 

Vent  without  the  genital  plates, 
never  opposite  the  mouth. 


Cidaridse. 

Hemicidaridse. 

Diademadse. 

Echinidae. 

Salenidse. 

Echinocouidse. 

Collyritidse. 

Echinonidse. 

Echinobrissidse. 

Echinolampidae. 

Clypeasteridse. 

Echinocoridse. 

Spatangidse. 


Famili/  \.  Cidarid^. — ^Test  thick,  spheroidal;  iiiter-ambulacral  areas  very  wide; 
primary  tubercles  large,  perforated ;  bosses  crenulated  or  uncrenulated,  spines  large, 
thick,  mostly  claviform ;  ambidacral  areas  very  narrow  ;  poriferous  zones  narrow,  pores 
nnigeminal,  rarely  bigeminal ;  mouth-opening  large,  inferior,  central,  circular  or  penta- 
gonal ;  peristome  destitute  of  notches,  always  armed  with  large,  powerful  jaws.  Vent- 
opening  wide,  superior,  opposite  the  mouth,  surrounded  by  five  large  genital  plates 
perforated  for  the  ovarial  canals,  and  five  small  ocular  plates  excavated  for  lodging  the 
eyes ;  buccal  and  anal  membranes  covered  with  scales. 

Types.      Cidaris  clavigera,  Ktinig  (PI.  IV).      Cidaris  scepfrifera,  Mantell  (PI.  VI). 

Family  2.  Hemicidarid^. — Test  thick,  spheroidal,  or  more  or  less  depressed ;  ambu- 
lacral  areas  narrow  or  wide,  with  semi-tubercles  at  their  base  only,  or  extended  throughout 
the  area ;  inter-ambulacral  areas  with  two  rows  of  primary  tubercles,  rarely  more  than 
eight  in  each  row ;  tubercles  of  both  areas  perforated,  and  bosses  deeply  crenulated ; 
poriferous  zones  narrow  and  undulated ;  pores  unigeminal  throughout,  except  near 
the  peristome,  where  they  are  bigeminal  and  trigeminal.  Mouth-opening  large  ;  peristome 
decagonal,  and  divided  more  or  less  deeply  by  notches  into  ten  lobes  ;  jaws  large  and 
powerful ;  apical  disc  small,  opposite  the  mouth,  composed  of  five  genital  and  five 
ocular  plates.  Spines  long,  thick,  cylindrical,  tapering,  claviform,  or  stout,  compressed, 
or  angular;  surface  smooth,  or  covered  with  fine  longitudinal  lines,  as  far  as  known, 
neither  prickles  nor  asperities  are  developed  thereon. 

Types.     Hemicidar is  intermedia,  Fleming.     Acrocidaris  formosa,  Agassiz. 


Family  3.  Diademad^. — Test  thin,  circular,  or  pentagonal,  more  or  less  depressed  ; 


CLASSIFICATION.  31 

aiiibulacral  areas  wide,  with  two  or  foiu'  rows  of  primary  tubercles  ;  inter-ambulacral  areas 
with  two,  four,  six,  or  more  rows  of  tubercles,  nearly  of  the  same  size  and  structure  as 
those  of  the  ambulacra;  tubercles  perforated  or  imperforated,  crenulated  or  uncrenu- 
lated,  in  different  genera ;  apical  disc  small,  opposite  the  mouth,  composed  of 
five  genital  and  five  ocular  plates ;  poriferous  zones  narrow ;  pores  unigeminal  or 
bigeminal.  Mouth-opening  large  and  decagonal ;  peristome  divided  into  ten  lobes  by 
deep  notches  ;  spines  long,  cylindrical,  more  or  less  slender,  either  tubular  or  solid  ; 
sometimes  encircled  by  spiral  verticillate  processes,  or  their  surface  is  sculptured  with  fine 
longitudinal  lines. 

Types.  Astropyga  radiata,  Leske.  Cyphosoma  Kcenigii,  Mantell.  Pseudodiadema 
tumidi/iH,  Forb. 

Family  4.  Echinid.e. — Test  thin,  spheroidal ;  inter-ambulacral  areas,  with  small 
primary  tubercles,  of  various  sizes,  perforate  or  imperforate;  bosses  crenulate  or  un- 
crenulate ;  ambiilacral  areas  wide,  always  supporting  two  or  more  rows  of  primary 
tubercles ;  poriferous  zones  narrow  or  wide,  pores  unigeminal,  trigeminal,  or  polygeminal, 
and  disposed  in  arcs  ;  spines  short,  mostly  subulate.  Mouth-opening  large,  inferior, 
always  decagonal ;  peristome  divided  into  lobes  by  notches  more  or  less  deep.  Vent 
small,  superior,  opposite  the  mouth,  surrounded  by  five  genital  and  five  ocular  plates ; 
buccal  membrane  naked. 

Types.     Echinus  sphcera,  Miiller.     Codiopsis  Donia,  Desmarest. 

Family  5.  Salenid^. — Test  thin,  spheroidal;  inter-ambulacral  areas  wide,  with  few 
primary  tubercles,  either  perforate  or  imperforate,  crenulate  or  uncrenulate ;  ambulacral 
areas  narrow,  carrying  secondary  tubercles.  Mouth-opening  small  or  large,  inferior, 
decagonal ;  peristome  more  or  less  notched.  Vent  superior,  surrounded  by  the  plates  of 
a  large  apical  disc,  composed  of  more  than  ten  pieces,  occupying  a  wide  aperture  in  the 
superior  part  of  the  test.  Poriferous  zones  narrow,  pores  unigeminal,  except  near  the 
peristome,  where  they  are  trigeminal.  Spines  long,  subulate,  circular,  or  flattened. 
Species  all  extinct ;  the  genera  distributed  in  the  Oolitic,  Cretaceous,  and  Tertiary 
rocks. 

Types.  Salenia  peialifera,  Defrance.  Acrosalenia  hemicidaroides,  Wright.  Gonio- 
phorus  lunidatus,  Agassiz.     Hyposalenia  Wrigldii,  Desor. 

Family  6.  EchinoconiDjE. — Test  thin,  circular,  elongated  or  pentagonal,  elevated  or 
depressed  ;  inter-ambulacral  areas  wide,  ambulacral  areas  narrow ;  external  surface  of 
the  plates  covered  with  numerous  small,  perforated,  and  crenulated  tubercles ;  pori- 
ferous zones  narrow,  pores  unigeminal,  except  near  the  base,  where  they  are  trigeminal. 
Mouth-opening  inferior,  central,  circular,  or  pentagonal,  armed  with  five  jaws ;  peristome 


32  ECHINOIDEA. 

notched,  dividing  the  circumference  into  ten  nearly  equal  lobes.  Apical  disc  central, 
superior,  composed  of  tive  genital  and  five  ocular  plates;  madreporiform  body  large, 
extending  from  the  right  antero-lateral  genital  plate  into  the  centre  of  the  disc.  Vent 
situated  at  the  upper  surface,  in  the  margin,  or  at  the  inferior  surface  of  the  test.  Spines 
small,  short,  subulate.  Species  all  extinct ;  genera  distributed  in  the  Oolitic  and 
Cretaceous  rocks. 

Types.  Ecldnoconus  alho-galerus,  Klein.  Tygaster  seviisulcatus,  Phillips.  Discoidea 
cylindrica,  Lamarck. 

Family  7.  Collyritidjj;. — Test  thin,  circular,  or  oval ;  ambulacral  areas  meeting  at 
two  points,  more  or  less  apart,  on  the  upper  surface ;  poriferous  zones  narrow,  pores 
unio-erainal ;  tubercles  small,  numerous,  perforated,  and  crenulated.  Mouth-opening  ex- 
central,  small,  round,  oval ;  peristome  feebly  fissured ;  jaws  unknown.  Vent  round, 
oval,  supra-marginal ;  elements  of  the  apical  disc  detached ;  four  genital  holes.  Species 
all  extinct,  and  distributed  in  the  Oolitic  and  Cretaceous  rocks. 

Types.     CoUyrites  ringens,  DesmouHns.      Collyrites  ovalis,  Parkinson. 

Family  8.  EcHiNONiDiE. — Test  thin,  oval ;  poriferous  zones  narrow,  meeting  at  the 
apical  disc ;  pores  unigeminal ;  tubercles  of  both  areas  nearly  equal,  neither  perforated 
nor  crenulated  ;  spines  stout,  subulate.  Mouth-opening  nearly  central,  irregularly  penta- 
gonal, and  edentulous.  Vent  oblong  or  pyriform,  basal  or  marginal,  closed  by  anal 
plates ;  apical  disc  nearly  central ;  four  genital  pores.  One  group  living  in  tropical  seas  ; 
another  fossil  in  the  Cretaceous  rocks. 

Types.     Echinoneus  cyclostomics,  Leske.     Pyrina  Desmoulinsii,  D'Archiac. 

Family  Q.  Echinobrtssid.e. — Test  thin,  circular,  oblong,  sub-pentagonal  or  clypeiform, 
covered  with  microscopic  perforate  tubei'cles,  surrounded  by  excavated  areolas  ;  ambulacra 
narrow,  enclosed  by  poriferous  zones,  more  or  less  petaloidal ;  pores  set  at  different  distances 
apart,  and  united  by  connecting  sutures.  Mouth-opening  small,  nearly  central,  pentagonal, 
edentulous,  in  general  surrounded  by  five  lobes.  Vent,  opening  in  a  sulcus,  in  the 
upper  surface  of  the  single  inter-ambulacrum,  or  in  a  marginal  depression  thereof;  apical 
disc  small,  four  genital  plates ;  madreporiforra  body  extending  into  the  centre  of  the 
disc.  Species  living  and  extinct,  the  latter  distributed  in  the  Oolitic,  Cretaceous,  and 
Tertiary  rocks,  the  former  in  the  seas  of  New  Holland,  and  the  Antilles. 

Types.  Ecliinohrissus  clutiicularis,  Llhwyd.  Clypeus  Plotii,  Leske.  Catopygus  carinafus, 
Goldfuss.     Pygaulus  cylindricus,  Desor. 

Family  10.  Echinolampid^. — Test  thin,  oblong,  oval,  elevated,  or  sub-discoidal ; 
ambulacra  large,  petaloid  ;  poriferous  zones  wide ;  pores  apart,  and  united  by 
suture ;  zones  extending  near  to  the  margin.     Mouth  small,  surrounded    by  five   lobes. 


TERMINOLOGY.  33 

Vent  transversely  oblong,  and  infra-marginal ;  apical  disc  small,  excentral,  with  four 
genital  holes.  Some  species  are  now  living  in  warm  seas,  but  the  greatest  number  are 
extinct,  and  distributed  in  the  Oolitic,  Cretaceous,  and  Tertiary  rocks. 

Types.     Conodypus   Leskei,    Goldfuss.      Echinolampas   orientalis,    Gray.      Pygurus 
Koeniyi,  Gray. 

Family  W.  Clypeasterid^. — Test  thick,  elevated  or  depressed,  circular,  elliptical,  or 
pentagonal;  surface  closely  covered  with  small,  nearly  equal-sized  tubercles,  sunk  in 
the  plates,  and  surrounded  by  ring- like  areolas,  tubercles  carrying  short  hair-like  spines. 
Mouth  large,  central,  and  pentagonal,  armed  with  five  strong  jaws,  containing  the 
same  number  of  teeth.  Vent  posterior,  marginal  or  infra-marginal ;  interior  of  the 
test  divided  by  pillar-like  processes,  formed  of  the  inner  layer  of  the  plates.  The  dorsal 
portions  of  the  ambulacral  areas  have  a  petaloid  form,  circumscribed  by  large  poriferous 
zones ;  the  basal  portions  are  narrow,  rectilineal,  or  branched ;  the  five  genital 
plates  form  a  circle  round  the  madreporiform  body,  and  between  these  are  wedged  the 
five  ocular  plates.  This  family  includes  the  genera  Cli/peaster,  Lamk.,  Layanum,  Klein, 
Echinarachnius,  Van  Phels.,  Araclmoides,  Klein,  Scutella,  Lamk.,  Bendraster,  Agass., 
Lobophora,  Agass.,  Encope,  Agass.,  Echinodiscus,  Breynius,  Mellita,  Klein,  Buna,  Agass., 
Moulinda,  Agass.,  ScuteUina,  Agass.,  Echhiocyamus,  Van  Phels.,  Fibularia,  Lamk., 
Lenita,  Desor. 

Types.     Clypeader  rosaceus,  Lamarck.     Scutella  suhrotunda,  Lamarck.     Ecldnarach- 
nius  placenta,  Gmelin. 

Family  12.  EcHiNOcoRiDiE. — Test  thick,  oval  or  cordate,  and  sometimes  conoidal; 
ambulacral  areas  contracted ;  poriferous  zones  narrow,  pores  unigeminal ;  test  covered  with 
small  perforated  and  crenulated  tubercles.  Mouth  small,  excentral,  tranversely  oblong. 
Vent  nearly  of  the  same  size,  oblong,  marginal  or  supra-marginal.  Apical  disc  elongated, 
nearly  central,  with  four  genital  pores ;  the  cordate  forms  have  an  anterior  central  depres- 
sion, and  one  genus  has  a  marginal  fasciole.  The  species  are  all  extinct,  and  limited  to 
the  Cretaceous  rocks. 

Types.  Echinocorys  vulyaris,  Breynius.  Ilulaster  subglobosus,  Leske.  Cardiaster 
granulosus,  Goldfuss. 

Family  13.  Spatangid^. — Test  thin,  oval,  oblong  or  cordiform,  exhibiting  the  bila- 
teral symmetry  of  the  Echinoidea.  Vent  posterior  and  supra-marginal,  closed  by  a  com- 
phcated  series  of  small  plates.  Apices  of  the  ambulacral  areas  united  at  the  summit  of 
the  test.  The  single  ambulacrum  has  a  different  structure  from  the  antero-  and  postero- 
lateral pairs,  and  is  lodged  in  general  in  a  depression  of  the  test,  which  extends  to  the 
anterior  border,  and  forms  the  anteal  sulcus;  test  extremely  thin,  and  covered  with 
small  tubercles,  which  support  hair-hke  spines.      Besides   these   there   are  some  larger 

5 


34  ECHINOIDEA. 

crenulated  and  perforated  tubercles  for  supporting  large  spines.  There  are  two  or  four 
genital  pores,  placed  close  together  in  some  genera,  but  apart  in  others.  The  eye- 
plates,  five  in  number,  are  situated  at  the  apices  of  the  ambulacra,  in  a  pentagonal  form, 
around  the  genital  plates.  On  the  surface  of  the  test  of  some  Spatan(/id(B  certain  delicate 
lines  are  observed,  having  a  smoother  appearance  than  the  tubercular  surface  of  the  test ; 
these  are  the /asc?o/(?s,  which  are  strewed  with  microscopic  tubercles,  and  destined  to  carry 
very  delicate  spines.  The  fascicles  have  a  different  disposition  in  each  genus,  and  afford  a 
good  character  in  making  definitions  of  the  same.  When  the  fasciole  surrounds  the 
ambulateral  petals  like  an  undulating  groove,  as  in  Hcmiaster,  Schizaster,  &c.,  it  is  jjeri- 
petalous ;  when  it  surrounds  the  single  ambulacrum,  as  in  Amjjhidetus,  it  is  internal; 
when  it  extends  along  the  sides,  as  in  ScMzaMer,  it  is  lateral ;  when  it  surrounds  the 
circumference  of  the  test,  as  in  Pericosmus,  it  is  marginal ;  when  it  is  limited  to  the  base 
of  the  anal  opening,  it  is  sub-anal.  Sometimes,  in  the  same  genus,  more  fascioles  than  one 
exist ;  thus  tlie  sub-anal  and  peri-petalous  are  frequently  associated  together. 

Types.     SjMtangus  purpureas,  Miiller.     Brissu^  lyrifer,  Forbes.     Brissopsis  Duciei, 
Wright. 


CIDARIDJE.  •  35 


Family  1 — Cidarid^. 

Test  thick,  turban-shaped,  more  or  less  depressed  at  the  oral  and  anal  apertures. 
Mouth-opening  wide,  central ;  peristome  circular  or  pentagonal,  without  notches ; 
aperture  closed  by  a  buccal  membrane,  covered  with  small  spines,  metamorphosed  into 
imbricated  scales,  upon  which  the  pores  from  the  zones  are  prolonged. 

Opening  for  the  apical  disc  very  large ;  disc  composed  of  five  large,  equal-sized, 
angular,  genital  plates,  and  five  ocular  plates  ;  vent  opening  in  the  centre,  directly  opposite 
the  mouth  ;  anal  membrane  clothed  with  small  angular  plates,  unequal  in  size,  and  variable 
in  number. 

Ambulacral  areas  extremely  narrow,  composed  of  a  great  number  of  very  small  plates, 
having  only  minute  tubercles,  or  rows  of  small  granules  on  their  surface,  and  never 
supporting  tubercles  with  primary  spines. 

Inter-ambulacral  areas  very  wide,  composed  of  large  plates,  rarely  more  than  from  six 
to  eight  in  a  column  ;  the  external  surface  of  each  plate  carries  a  large  perforated 
tubercle,  raised  on  a  prominent  boss,  and  encircled  by  a  round  or  oval  areola,  having 
an  elevated  margin,  on  which  are  a  circle  of  granules,  usually  larger  than  those  filling  the 
miliary  zone. 

Poriferous  zones  narrow,  extending  without  interruption  from  the  margin  of  the  buccal 
membrane  to  the  apical  disc  ;  pores  in  general  unigeminal,  in  one  genus  bigeminal ;  pores 
contiguous,  or  separated  by  septa  more  or  less  thick. 

Jaws,  five  in  number,  forming  a  very  powerful  lantern,  moveably  connected  with,  and 
supported  by,  a  series  of  calcareous  processes  or  auricles,  arising  from  the  inner  surface 
of  the  test ;  the  teeth  are  more  simple,  and  the  lantern  less  complicated  than  in  the 
Ecldnidce. 

The  spines  in  this  family  exhibit  a  great  variety  of  forms,  they  are  large,  strong,  cylin- 
drical, fusiform,  prismatic,  club-shaped,  or  flattened;  and  their  surface  is  covered  with 
fine  longitudinal  lines,  or  with  prickles  or  granules,  having  in  general  a  linear  arrange- 
ment, or  a  more  or  less  irregular  disposition  ;  the  form  and  sculpture  of  the  spine  has  a 
specific  value,  as  its  dominant  characters  appear  to  be  persistent.* 

The  Cidaridis  are  the  most  ancient  type  of  the  Echinoidea.  The  remains  of  different 
forms  of  this  family  are  found  in  the  Palaeozoic  rocks,  as  well  as  in  those  of  the  Secondary 

*  The  form  and  general  character  of  the  spine  should,  in  every  case,  be  examined  with  scrupulous 
attention,  and,  whenever  in  fossil  species  the  spines  are  found  attached  to  their  test,  the  facts  connected 
tiierewith  should  be  noted  with  the  greatest  accuracy.  The  neglect  of  this  caution  has  been  the  cause  of 
much  confusion,  and  led  to  some  serious  errors. 


36  CIDARIS 

and  Tertiary  epochs.  In  his  valuable  Synopsis,  M.  Desor  describes  six  genera  in  this 
family :  these  are  Cidaris,  Klein ;  Rabchcidaris,  Desor ;  Diplocidaris,  Desor  ;  Porocidaris, 
Desor ;  Goniocidaris,  Desor ;  Palceocidaris,  Desor.  Of  this  number  three  are  extinct — 
Bijilocldaris,  Porocidaris,  and  Palceocidaris ;  two  contain  both  extinct  and  living  forms 
— Cidaris  and  Babdocidaris ;  and  one  is  only  found  living — Goniocidaris. 


A. — Species  from  the  Gault. 

Cidaris  Gaultina,  Forbes,  MS.     PI.  I,  fig.  2,  a,  b,  c,  d,  e ;  fig.  3,  a,  b ;  fig.  4  a,  b,  c. 

CiDAEis  Gaultina,  Forhes.     Morris's   Catalogue   of  Britisli  Fossils,  2nd  ed.,  p.  74, 
1854. 
—  —  Woodward.     Memoirs  of  the  Geological  Survey,  Decade  v,  e.xpl., 

pi.  V,  1856. 

The  specimen  figured  in  PL  I,  fig.  2,  belongs  to  the  British  Museum,  and  was  kindly 
communicated  by  my  friend,  S.  P.  Woodward,  Esq.,  F.G.S.  It  consists  of  five  inter- 
ambulacral  plates,  and  a  trace  of  an  ambulacral  area,  with  a  number  of  spines.  Detached  plates 
of  this  urchin  resemble  those  of  Cidaris  vesiculosa,  Goldf.  In  the  large  plate  (fig.  2,  b), 
magnified  two  and  a  half  times,  the  depth  is  greater  than  the  breadth ;  the  wide  circular 
areola  is  nearer  the  lower  border,  its  margin  is  elevated,  and  surrounded  by  a  circle  of  thirteen 
small  tubercles,  each  set  upon  a  distinct  base  ;  the  boss  is  flat,  its  summit  smooth,  and 
the  tubercle  large  and  distinctly  perforated  ;  the  rest  of  the  plate  is  covered  with  a  fine 
clo.se-set  granulation  (fig.  2,  a,  b). 

The  remaining  fragment  of  the  ambulacral  area  is  too  imperfect  for  description. 

The  spines  vary  in  form ;  they  are  in  general  long  and  slender,  and  taper  slightly 
(figs.  2  and  3).  The  surface  is  covered  with  longitudinal  ridges,  the  edges  are  distinctly 
serrated  (fig.  2,  a,  and  fig.  3,  b),  and  the  stem  represents  a  miniature  fluted  column.  The 
truncated  summit  shows  a  star-like  structure  (fig.  2,  e),  produced  by  the  serrated  ridges 
meeting  around  the  circumference  of  a  central  circle.  The  neck  is  smooth,  short,  and 
thick  (fig.  2,  d,  and  fig.  3,  b) ;  the  milled  ring  broad  and  flat,  and  covered  with  very  fine 
lines ;  the  head  is  short,  and  the  acetabulum  surrounded  by  a  line  (fig.  2,  d). 

In  one  of  the  broken  spines  that  accompanies  the  plates  the  upper  extremity  is 
expanded  and  cup-like  (fig.  4,  a,  b,  c),  whilst  in  the  other  spines  the  extremities  are 
contracted  and  truncated  (fig.  2,  a,  c). 

Affinities  and  differences. — This  urchin  very  closely  resembles  Cidaris  vesiculosa,  Goldf., 
found  in  the  Chalk-marl  of  Essen  and  Ruhr.  The  resemblance  is  so  great  between  the 
German  and  English  forms,  that  without  a  comparison  of  specimens  a  correct  diagnosis 


FROM  THE  G/VULT  AND  GREENSAND.  37 

cannot  be  given.  In  Cidaris  vesiculosa,  Goldf.,  the  marginal  circle  of  areolar  tubercles 
is  not  so  prominent  as  in  Cidaris  Gaulfina,  Forb.,  but  the  general  character  of  the 
ornamentation  on  the  plates  is  the  same  in  both.  The  spines  figured  by  Goldfuss 
closely  resemble  those  of  C.  Gaidtina ;  they  have  the  same  slender,  elongated  form,  and 
fluted  structure ;  most  of  them  are  spindle-shaped,  and  some  have  an  expanded  cup-like 
termination,  like  the  spine  fig.  4,  a. 

Locality  and  Stratigraphical  Position. —  Cidaris  GauUina  is  a  very  rare  urchin.  I 
only  know  the  specimens  contained  in  the  Museum  of  the  Royal  School  of  Mines,  and  the 
subject  of  our  figures,  which  belongs  to  the  British  Museum ;  both  these  fossils  were 
obtained  from  the  Gault  at  Folkstone.  Cidaris  vesiculosa,  Goldf.,  on  the  contrary,  has 
been  collected  from  the  Chalk-marl  of  Germany,  and  the  Grey  Chalk  at  Dover. 


B. — Species  from  the  Upper  Greensand. 

Cidaris  velifera,  Bronn.     PI.  II,  fig.  2  a,  b,  c,  d,  e,f;  fig.  '6  a,  b ;  fig.  4  a,  b. 

Cidaris  VELirERA,     Bronn.     Jahrb.,  p.  154,  the  name  only,  1835. 

—  pisiFERA,      Agassiz.     Catalogus  Systematicus,  p.  10,  1840. 

—  VELiFER,        Bronn.     Index  Palceontologicus  ("  =  iSa/e^iVe  sp."),  1848. 
— ■      MicHELiNi,  Sorignet.     Ours.  Foss.  de  I'Eure,  p.  18,  1850. 

—  GLOBICEPS,   Qwenstedt.     Handbuch   der   Petrefactenkunde,   p.    577,    pi-    49, 

fig.  17,  1852. 

—  VELIFERA,     Woodward.     Mem.  Geol.  Surv.,  Decade  v,  pi.  v,  1856. 

—  Heberti,      Besor.     Synopsis  des  Echinides  Fossiles,  p.  12,  1858. 

—  velifera,    Desor.     Ibid.,  p.  34,  1858. 

—  —  Cotieau.     Paleont.  rran9aise  ;  Echinides,  pi.  1054,   figs.   14 — 21, 

p.  241. 

Test  small,  circular,  depressed ;  ambulacral  areas  narrow  and  sinuous,  with  four  rows 
of  granules;  inter-ambulacral  areas  wide,  tubercles  large  and  prominent,  gradually 
increasing  in  size  from  the  peristome  to  the  apical  disc,  where  they  are  globose  and  con- 
spicuous ;  spines  short,  stems  large  and  globular,  surface  covered  with  longitudinal  rows 
of  pustular  elevations. 

Dimensions. — Height,  three  tenths  of  an  inch ;  transverse  diameter,  eleven  twentieths 
of  an  inch. 

Bescriptioti. — This  beautiful  little  Cidaris  is  one  of  the  oldest  representatives  of  the 
group  possessing  claviform  spines,  Sadioli  j/latidarii,  for  all  doubt  about  the  identity  of  the 


38  CIDARIS 

test,  and  the  spine  appertaining  thereto,  is  removed  by  the  discovery  of  the  interesting 
specimen  fignred  in  PI.  II,  fig.  4,  a.  The  spines  of  this  species  were  first  discovered  in 
the  Craie  chloritce  of  Essen  and  Frohnhansen,  and  were  named  by  Bronn  veJifcr ;  as  the 
asperities  on  tlieir  globnlar  stem  impart  a  pecuhar  character  to  them,  and  that  autlior,  in 
his  'Index  Palseontologicus,'  referred  them  to  a  Salenia.  M.  Desor  described  a  small 
Cidaris  Heberti  from  the  Craie  chloritee  of  Cap  la  Heve,  Avhich  I  believe  to  be  the  test  of 
this  species.  The  short  diagnosis  given  in  the  '  Synopsis '  agrees  so  well  with  the  speci- 
mens before  me  that  I  have  no  hesitation  in  conclnding  it  to  be  the  same: — "Petite  espece 
a  scrobicules  petits  et  serves,  mais  a  tahercules  trcs-r/ros,  surtout  a  la  face  siijjerieure. 
Quafre  rangees  cle  granules  ambulacraires." 

The  ambnlacral  areas  are  slightly  sinnous,  and  furnished  with  four  rows  of  small 
granules  (fig.  2,  e)  closely  set  together,  the  marginal  rows  being  the  most  uniform  in  their 
arrangement.  The  narrow  poriferous  zones  lie  in  a  deep  groove  formed  by  the  prominence 
of  the  adjoining  granules  ;  the  pairs  of  small  holes  are  obliquely  inclined,  with  thickened 
septa,  each  having  a  small  tubercle  (fig.  2,  e)  between  thein. 

The  inter-ambulacral  areas  have  two  rows  of  tubercles  placed  so  near  the  poriferous 
zones  that  the  inter-tubercular  space  in  the  middle  of  the  area  is  about  the  same  width  as 
the  ambulacra,  whereby  the  ten  rows  of  tubercles  are  situated  nearly  equidistant  from  each, 
thus  imparting  a  regular  appearance  to  this  species  (fig.  2,  c,  b).  There  are  five  tubercles 
in  each  row,  which  increase  gradually  in  size  from  the  peristome  to  the  disc ;  the  three 
basal  tubercles  are  small  and  set  closely  together  (fig.  2,  b),  whilst  the  two  upper  tubercles 
are  large  and  wide  apart  (fig.  2,  f);  the  mammillary  eminence  is  depressed,  the  areolae  are 
narrow  (fig.  2,  e),  and  their  margin  surrounded  by  a  circle  of  well-defined  granules 
(fig.  2,/).  The  tubercle  is  large  and  prominent,  and  the  narrow  boss  on  which  it  rests 
is  destitute  of  crenulations  (fig.  2,  e,f) ;  the  summits  of  all  the  tubercles  are  perforated,  those 
on  the  upper  part  of  the  test  are,  however,  best  preserved.  A  broad  band  of  granula- 
tions separates  the  two  rows  of  tubercles ;  five  or  six  rows  of  granules  are  closely  placed 
together ;  and  the  granules  in  the  band  and  those  in  the  ambulacra  are  nearly  of  the  same 
size. 

In  the  specimen  figured  at  4,  a,  there  are  seven  spines  attached  to  the  test  in  their 
natural  order.  The  spines  (fig.  3,  a)  have  a  very  short  neck  and  a  large  globular  stem, 
covered  with  rows  of  pointed  elevations  (fig.  3,  b)  rising  from  the  midst  of  an  apparently 
villous  surface.  The  milled  ring  (fig.  4,  b)  is  close  to  the  acetabulum,  it  is  moderately 
prominent,  and  crowded  with  fine  lines.  From  the  manner  in  which  these  globular  spines 
are  arranged  on  this  small  test,  very  little  individual  motion  was  possible  among  them, 
and  yet  the  delicate  surface  of  the  spines,  when  examined  with  a  lens,  gives  no  evidence  of 
abrasion,  from  the  friction  of  moveable  bodies  laid  so  closely  together  as  these  spines  were 
placed. 

Affinities  and  differences. — The  test  of  this  beautiful  little  Cidaris  is  nearly  related  to 


FROM  THE  GREY  CHALK.  39 

Cidaris  davigera,  Koiiig,  both  in  the  form  of  the  tubercles  and  the  narrowness  and  depth 
of  the  areolae  ;  but  in  the  structure  of  the  spines  there  is  a  manifest  difference,  which  will 
be  more  fully  appreciated  by  comparing  PI.  IV,  fig.  1,  exhibiting  a  series  of  spines  of 
C.  clavigera,  with  PI.  H,  fig.  3,  b,  showing  a  magnified  view  of  the  spine  of  C.  velifera. 

Locality  and  Stratigrapldcal  Position. — W.  Cunnington,  Esq.,  F.G.S.,  of  Devizes,  to 
whom  I  am  indebted  for  the  loan  of  specimens  of  this  species,  obtained  them  from  the 
Upper  Greensand  near  Warminster ;  I  had  seen  the  plates  of  the  test  and  portions  of  the 
spines,  but  never  before  have  I  seen  these  parts  "  in  situ.^' 

»  The  foreign  distribution  of  this  urchin  is  as  follows  : — The  spines  are  found  in  the 
Craie  chloritee  of  Essen,  Prussia,  and  of  Frohnhausen,  Hesse-Cassel,  and  the  test, 
described  under  the  name  Cidaris  Ileberti,  Des.,  was  collected  from  the  Craie  de 
Vendorae,  from  the  Craie  chloritee  du  Cap  la  Heve  and  la  Madeleine,  near  Vernon 
(Eure)  in  I'Etage  Cenomanien,  where  it  is  very  rare. 


C. — Species  from  the  Greg  Chalk. 

Cidaris  Carteri,  Forbes.     PI.  I,  fig.  1,  a,  b,  c,  d,  e,f. 

Cidaris  Carteri,  Forbes.     Memoirs  of  the  Geol.  Survey,  Decade  v,  pi.  v,  1854. 

—  —       Morris.     Morris's  Catalogue  of  Brit.  Fossils,  2tid  ed.,  p.  74,  1856. 

—  —        Desor.      Synopsis  des  Echinides  Fossiles,  p.  12,  1858. 

Test  small,  inflated,  subconical;  ambulacral  areas  narrow,  winding,  with  two  marginal 
rows  of  moniliform  granules,  and  a  deep  median  sulcus ;  inter-ambulacral  areas  wide ; 
tubercles  small,  remote ;  areolae  at  the  equator  narrow,  complete,  those  on  the  upper  plates 
small,  elongate,  and  obsolete. 

Dimensions. — Pleight,  eight  lines ;  transverse  diameter,  ten  lines. 

Description . — Should  subsequent  discovery  confirm  the  opinion  that  this  is  an  adult 
test,  it  will  be  the  smallest  Cidaris  in  the  English  Chalk.  It  very  much  resembles,  in 
many  points  of  structure,  Cidaris  sceptrifera,  Mant.,  from  which  it  differs,  however,  in 
size  and  figure,  and  in  the  development  of  the  tubercles  and  their  areolae,  especially  those  on 
the  upper  plates.  The  ambulacral  areas  are  narrow  and  winding  ;  they  have  two  rows  of 
prominent  moniliform  granules  on  the  extreme  margins  of  the  areas  (fig.  1,  c) ;  and  in  the 
depth  of  one  equatorial  inter-ambulacral  plate  I  have  counted  sixteen  of  these ;  between 
them  is  a  deep  sulcus,  on  which  two  indistinct  central  rows  of  microscopic  granules  are 
sparsely  distributed. 


40  CIDA.RIS 

The  inter-aml:)ulacral  areas  are  wide,  and  consist  of  large,  deep  plates  (fig.  1,  c),  about 
four  or  five  in  each  row,  those  at  the  equator  are  the  largest ;  the  tubercle  is  small 
and  perforated ;  the  boss  is  flat,  with  a  smooth  summit ;  the  areolae  are  narrow  and 
complete,  and  encircled  by  a  moniliform  circle  of  sixteen  small  granules,  raised  on 
scale-like  plates  (fig.  1,  <?) ;  from  the  equator  to  the  mouth  the  tubercles  and  their 
areolae  gradually  diminish  in  diameter,  and  on  the  upper  surface  the  plates  tbey  are  very 
deep,  and  their  areolae  small,  elongated,  and  entirely  obsolete ;  the  inter-tubercular  surface 
of  the  plates  is  covered  with  close-set  miliary  granulations. 

The  poriferous  zones  are  narrow  and  deeply  sunk,  in  consequence  of  the  thickness  of 
the  plate-ornamentation ;  the  holes  are  small,  the  pairs  oblique,  and  there  are  sixteen 
pairs  opposite  one  large  inter-ambulacral  plate,  one  pair  of  holes  being  opposite  one  of  the 
large  marginal  ambulacral  granules. 

The  apical  disc  is  wide,  occupying  all  tlie  summit  of  the  test  (fig.  1 ,  a,  b) ;  the 
ovarial  plates  are  large  (fig.  1,  c/),  and  of  an  irregular  rhomboidal  figure ;  their  surface  is 
covered  with  small  granules  sparsely  distributed  thereon,  and  the  oviductal  holes  are 
perforated  at  the  outer  third  of  the  plates.  The  oculars  are  small  and  heart-shaped,  and 
intercalated  between  the  angles  formed  by  the  ovarials  ;  the  orbits  appear  to  have  been 
marginal. 

Affinities  and  differences. — This  species  resembles  Cidaris  scejjfrifera,  Mant.,  but  the 
depth  of  the  inter-ambulacral  plates  and  the  limited  number  in  a  column,  together  with 
the  sraallness  of  the  areolae  and  the  obsolete  character  of  those  on  the  upper  plates,  prove 
that  this  urchin  is  quite  distinct  from  that  form. 

Locality  and  Stratigraphical  Position. — The  only  specimen  at  present  known  was 
collected  by  James  Carter,  Esq.,  F.G.S.,  of  Cambridge,  from  the  Grey  Chalk  of  that 
neighbourhood  ;  and  it  belongs  to  his  collection.  In  Morris's  '  Catalogue '  it  was  stated  by 
mistake  to  have  come  from  the  White  Chalk,  and  in  M.  Desor's  '  Synopsis,'  from  the  Ores 
vert  superieure  d'Angleterre. 

Hislorij. — This  species  was  first  figured  in  the  '  Memoirs  of  the  Geological  Survey,' 
in  plate  v  of  the  Fifth  '  Decade  of  British  Organic  Remains.'  The  original  specimen 
formed  the  subject  of  Mr.  Bone's  drawings  for  this  work. 


FROM  THE  GREY  CHALK.  41 


CiDARis  VESICULOSA,  Golclfms.     Plate  II,  fig.  5,  a,  b,  c,  d ;  Plate  III,  fig.  1,  a,  b,  c,  d,  e. 

CiUARis  VESICULOSA,  Goldfuss.     Petref.  Germanise,  t.  i,  p.  120,  pi.  xi,  fig.  2,  1826. 

—  —  Agassiz.     Prod.  Me'm.  Soc.  Nat.  de  Neuchatel,  torn,  i,  p.  188,  1836. 

—  —  Desmoulins.     Etudes  sur  les  Echiiiides,  p.  332,  No.  23,  1837. 

—  —  Bronn.     Lethsea  Geognostica,  p.  607,  pi.  xxix,  fig.  76,  1837. 

—  —  Geinitz.      Charakter    der    Schichten    und    Petrefacten    Kreide- 

gebirges,  p.  89,  pi.  -xxii,  fig.  1,  a,  b,  c,  d,  1839. 

—  —  Roemer.     Norddeutschen  Kreidegebirges,  p.  28,  1840. 

—  —  Bujardin,  in  Lamarck,  Anim.  sans  Vert.,  2e  ed.,   t.  iii,  p.  338, 

1840. 

—  —  Revss.     Versteinerungen  der  Biilim.   Kreideform.,  p.  57,  pi.  xx, 

fig.  14,  1845. 

—  —  Agassiz  et  Desor.      Catal.   rais.  des  £ch.    Ann.  des    Sc.    Nat., 

3e  serie,  t,  vi,  p.  328,  1846. 

—  _  Broyxn.     Index  Palfcont.,  p.  301,  1848. 

—  —  Quenstedt.     Handbuch  der  Petrefacktenkunde,  p.  575,  pi.  xlviii, 

fig.  47,  1852. 

—  SPINULOSA,     Guh-anger.     Essai  d'un  rep.  pale'ont.  de  la  Sarthe,  p.  40,  1853. 

—  VESICULOSA,  Desor.     Synopsis  des  Echinides  Fossiles,  p.  11,  pi.  v,  figs.  24, 

25,  1855. 

—  EffiMERi,         Cotteau,  in  Davoust,  Note  sur  les  Fossiles  speciaux  a  la  Sarthe, 

p.  49,  1855. 

—  VESICULOSA,  Pictet.     Traite  de  Paleont.,  2nd  ed.,  t.  iv,  p.  254,  1860. 

—  —  Cotteau   et    Triger.      Echinides  de  la    Sarthe,   p.    133,  pi.   xxv, 

figs.  1—6,  1860. 

—  —  Cotteau.     Note  sur  les  Echinides  recueillis  en  Espagne,  par  MM. 

Verneuil,  Triger,  et  Collomb.,  Bull,  de  la  Soc.  Ge'ol.  de  France, 
2e  serie,  t.  xvii,  p.  375,  1860 

—  —         Cotteau  in  D'Orbigny's  Paleontologie  Fran9aise,  t.  ii,  p.  222,  pi. 

1050,  and  pi.  1051,  figs.  1—6. 

Test  circular,  inflated,  nearly  equally  depressed  at  both  poles ;  ambulacral  areas  flexed, 
depressed  in  the  middle,  and  filled  with  from  six  to  eight  rows  of  close-set,  nearly  equal- 
sized  granules,  diminishing  to  two  or  four  rows  near  the  disc  and  peristome ;  poriferous  zones 
very  narrow,  and  flexuous  ;  pores  small,  having  a  moniliform  line  of  granules  separating  the 
pores ;  inter-ambulacra  wide,  four  to  five  plates  in  each  column ;  tubercles  moderate  in 
size,  perforated,  and  uncrenulated,  set  very  wide  apart  on  the  upper  half  of  the  test; 
areas  round,  superficial,  much  inflated  at  the  border,  and  surmounted  with  a  circle  of 
prominent,  mammillated  granules.  Near  the  disc  the  tubercles  on  the  alternate  columns 
become  dwarfed,  are  destitute  of  areolae,  and  occupy  the  middle  of  a  long  granular  plate ; 
miliary  zone  large,  much  depressed,  and  filled  with  small  equal-sized  granules ;  discal  and 
oral  apertures  about  the  same  diameter. 

6 


42  •  CIDARIS 

Dimensions. — Height,  nine  tenths  of  an  inch  ;  transvei'se  diameter  one  inch  and  a  half. 

Description. — This  urchin,  which  forms  so  characteristic  a  species  in  the  Lower  Chalk 
of  the  Continent,  as  shown  in  the  table  of  synonyms,  has  hitlierto  escaped  the  notice  of 
English  geologists.  The  species  from  our  Upper  Chalk,  en'oneously  referred  to  this  form, 
being  quite  distinct  from  the  true  Cidaris  vesiculosa,  Goldf.,  from  the  Gray  Chalk  and 
Upper  Greensand  ;  specimens  from  each  of  these  formations  I  have  figured  in  Pis.  II  and  III. 

The  test  is  of  moderate  size,  much  inflated  at  the  sides,  and  nearly  equally  depressed 
at  both  poles ;  the  ambulacral  areas  are  flexuous,  depressed  in  the  middle,  and  filled 
throughout  with  numerous  rows  of  small,  regular,  close-set,  equal-sized  granules  ;  at  the 
equator  there  are  eight  rows,  which,  near  their  terminations,  diminish  to  two  or  four  rows 
(PI.  Ill,  fig.  1,  d) ;  the  inner  rows  are  those  which  gradually  disappear,  whilst  the  outer 
rows  are  persistent  throughout. 

The  poriferous  zones  are  very  narrow,  following  the  flexures  of  the  ambulacra ;  they 
are  composed  of  small  round  pores,  separated  by  a  granule,  the  series  forming  a  moniliform 
line  down  the  middle  of  the  zone,  fig.  2.  d. 

The  inter-ambulacral  areas  are  composed  of  very  large  plates,  those  in  the  upper  half 
of  the  columns  being  the  largest  and  most  inflated  ;  there  are  from  four  to  five  plates  in 
each  series.  The  areas  are  circular  and  superficial,  with  very  prominent  borders  sur- 
rounded by  a  circle  of  distinct  regular  mammillated  granules  (PI.  Ill,  fig.  1,  d) ;  on  the 
under  half  of  the  test  the  tubercles  are  approximated  (PI.  Ill,  fig.  1,  b);  whilst  on  the 
upper  half  they  are  set  wide  apart,  from  the  increased  height  of  the  plates  (PI.  Ill,  fig.  1, 
a  and  c) ;  near  the  summit  the  uppermost  tubercles  on  the  alternate  columns  are  imperfectly 
developed,  and  often  destitute  of  areolse,  and  placed  in  the  middle  of  a  long  granular  plate 
(PI.  Ill,  fig.  1,  a  and  c).  The  tubercles  are  moderate  in  size,  and  perforated ;  the  summits 
of  the  bosses  are  quite  smooth,  and  without  any  trace  of  crenulations  (PI.  Ill,  fig.  1,  e). 

The  miliary  zone  is  large  and  much  depressed,  and  provided  with  numerous  flat, 
uniform  granules,  closely  set  together  on  the  entire  surface  of  the  plates  (fig.  \,  d). 

The  peristome  is  circular  (fig.  1  b),  and  the  opening  for  the  apical  disc  (fig.  1,  a)  is 
nearly  the  same  diameter  as  the  oval  aperture. 

The  spines  of  this  species,  according  to  M.  Cotteau,  are  elongated,  cylindrical,  sub- 
fusiform,  with  compressed  longitudinal  ribs,  more  or  less  spinous,  and  denticulated,  the 
processes  being  always  at  regular  distances  apart.  Towards  the  base,  the  ribs  diminish 
and  disappear,  and  the  stem  is  provided  only  with  fine,  close-set  striae.  The  neck  is  short 
and  striated,  the  milled  ring  prominent,  the  articular  head  smooth,  and  surrounded  by  a 
small  groove. 

Length,  twenty-five  to  thirty  millimeters  ;  thickness,  five  millimeters. 

Variety,  sj)inulosas,  Agassiz  :  length,  forty-seven  millimeters ;  thickness,  six  millimeters. 

Affinities  and  differences. — This  species  is  distinguished  from  Cidaris   sceptri/era, 


FROM  THE  GREY  CHALK.  43 

Mant.,  of  the  White  Chalk,  by  having  fewer  tubercles  in  the  columns,  which  are  wider 
apart  in  the  upper  portion  of  the  test ;  the  areolas  are  likewise  shallower,  and  the  border 
more  prominent.  In  Cidaris  scepMfera  the  tubercles  are  largely  developed  (PI.  VI,  VII), 
with  deep  areolas  surrounded  by  a  circle  of  prominent  granules,  and  with  a  narrow  sinuous 
miliary  zone.  The  spines  likewise  are  large  and  fusiform,  having  their  surface  covered  with 
prominent  spiny  granules.  Cidaris  vesiculosa,  Goldf.,  differs  from  C.  subvesiculosa,  d'Orbig., 
in  having  the  test  flatter,  the  tubercles  smaller,  less  numerous,  and  more  apart. 

The  specimens  of  this  urchin,  collected  from  the  Upper  Greensand  of  Wiltshire,  were 
by  the  late  Professor  Forbes^  referred  to  Cidaris  insiffiiis,  Gras.  Through  the  kindness  of 
my  friend  W.  Cunnington,  Esq.,  F.G.S.,  I  have  been  enabled  to  examine  the  beautiful 
series  of  this  species  in  his  collection,  and  in  PI.  II,  fig.  5,  have  figured  his  largest  and 
finest  specimen.  A  careful  study  of  these  fossils  has  satisfied  me  that  they  are  not  the 
species  described  by  Dr.  Albin  Gras,'  and  which  he  thus  characterized  : — "  Aires  ambula- 
craires  ondulees,  paraissant  presenter  deux  rangees  verticales  de  granules  tres  serrees  et 
rapprochees  les  unes  des  autres ;  probablement  cinq  tubercles  inter-anibulacraires  non 
creneles  dans  chaque  rangee  (quatre  paraissent  seulement  dans  notre  exemplaire,  dont  la 
partie  superieure  n)anque).  Sur  les  cinq  tubercles,  les  trois  inferieurs  augmentent  pro- 
gressivement  de  grandeur  en  allant  de  bas  en  haut ;  leurs  scrobicules  et  leurs  cercles  scro- 
biculaires  ronds,  saillants  et  formes  de  granules  serres,  sont  tres-prononces,  tangents  entre 
eux  et  avec  ceux  de  la  rangee  voisine ;  ils  sont  au  contraire  presque  effacee  dans  le  petit 
tubercle  qui  vient  ensuite,  lequel  diminue  brusquement  et  repose  pourtant  sur  une  tres- 
large  plaquette  couverte  de  norabreux  granules."  The  ambulacral  areas  in  C.  vesiculosa, 
Goldf.,  have,  at  the  equator,  six  rows  of  small,  equal-sized  granules,  closely  arranged  in 
parallel  lines,  and  diminishing  to  four  rows  at  the  narrowest  parts.  This  persistent 
structure  affords  a  character  by  which  the  species  is  distinguished  from  C.  insignis. 

The  British  Museum  contains  a  fine  specimen  of  C.  vesiculosa,  G(M.L,  from  the  Gray  Chalk 
of  Dover  (PL  III,  fig.  1).  This  test  I  have  carefully  compared  with  Mr.  Cunnington's 
Upper  Greensand  specimens,  and  the  examination  has  convinced  me  that  they  belong  to 
the  same  species  ;  the  test  of  the  specimen  from  the  Gray  Chalk  is  that  of  a  larger,  and 
older  individual;  some  of  the  plates,  however,  in  the  upper  part  of  the  columns,  are 
proportionally  more  inflated ;  but  in  all  other  respects  its  characters  are  identical  with 
those  of  the  Upper  Greensand  forms. 

The  test  is  spheroidal,  of  medium  size,  and  nearly  equally  depressed  at  both  poles ;  the 
ambulacral  areas  form  narrow,  flexuous,  granular  bands,  which  decline  towards  the 
central  suture ;  they  are  entirely  filled  with  small,  close-set,  equal-sized  granules,  arranged 
in  regular  parallel  rows,  of  which  there  are  from  six  to  eight  at  the  equator,  diminishing 
to  four  in  the  narrowest  parts,  near  the  peristome  and  apical  disc ;  the  poriferous  zones 

1  Morris,  '  Catalogue  of  British  Fossils,'  2ncl  ed.,  p.  74. 

2  'Description  des  Oursins  Fossiles  du  departemeiU  de  I'ls^re,'  p.  21,  1848. 


44  CIDARIS 

ai'e  very  narrow,  and  the  small  pores  are  placed  close  together,  each  septum  being  sur- 
momited  by  a  little  granule;  there  are  23  pairs  of  holes  opposite  one  of  the  large  plates. 

The  inter-ambulacral  areas  are  formed  of  large  deep  plates,  the  limits  of  which  are 
very  distinctly  defined  by  well-marked  sutural  lines ;  there  are  four  or  five  plates  in  each 
column,  those  at  the  lower  part  of  the  test  are  small  and  regular  (fig.  1,  b),  and  those  at  the 
upper  part  of  the  column  are  large,  deep,  and  rather  irregidar  in  figure,  from  the  extreme  pro- 
minence of  the  areolar  margin  (fig.  1,  a,  c);  each  plate,  with  the  exception  of  the  uppermost 
in  each  alternate  column,  supports  a  large  primary  tubercle ;  it  is  surrounded  by  a  shallow 
circular  areola  ;  the  boss  is  not  prominent ;  and  the  summit  is  smooth,  without  a  trace  of  cre- 
nulation ;  the  tubercle  is  large,  sessile,  and  perforated  (fig.  \,  e);  the  margin  of  the  areola  is 
very  prominent,  which,  in  the  larger  plates  especially,  produces  an  inflation  of  their  surface, 
and  probably  suggested  the  specific  name  vesiculosa  (fig.  \,a).  A  complete  circle  of  mammil- 
lated  granules,  larger  than  those  on  other  parts  of  the  test,  surrounds  the  margin  of  the  areolae, 
and  forms  a  prominent  boundary  thereto  (fig.  1,  d).  The  uppermost  plate  in  each  alternate 
column,  in  most  specimens,  is  either  destitute  of  a  tubercle,  or  represented  only  by  a  rudi- 
mentary warty  body,  without  areola,  and  situated  in  the  midst  of  a  long,  narrow, 
imperfectly  developed  plate,  on  all  sides  surrounded  by  granules. 

The  mouth  is  small  and  circular,  and  of  the  same  diameter  as  the  aperture  for  the 
apical  disc,  which  is  likewise  entirely  circular. 

Locality  and  Strafiffraphical  Position. — The  specimen  figured  in  Plate  III,  fig.  1,  be- 
longing to  the  British  Museum,  was  collected  from  the  Gray  Chalk,  at  Dover,  and  the  one 
figured  in  PL  II,  fig.  5,  belongs  to  my  friend  W.  Cunnington,  Esq.,  F.G.S.,  Devizes,  and  was 
obtained  from  the  Upper  Greensand  of  Wilts.  The  specimen  in  my  own  collection  is 
from  the  Gray  Chalk  of  Dover.  I  believe  this  urchin  is  very  rare,  as  I  have  seen  very 
few  specimens  in  the  different  collections  of  Cretaceous  fossils.  The  Rev.  T.  Wiltshire, 
F.G.S.,  has  communicated  a  fragment,  collected  from  the  Red  Chalk  of  Hunstanton  Cliff, 
together  with  three  detached  spines,  of  the  same  species.  1  am  inclined  to  refer  to  this 
species  the  specimen,  figured  in  PI.  Ill,  fig.  3,  collected  by  C.  B.  Rose,  Esq.,  F.G.S,, 
from  the  Red  Chalk,  and  kindly  communicated  for  this  work.  The  test  is  much  defaced 
by  friction,  but  still  many  of  the  more  remarkable  characters  of  the  urchin  are  well 
preserved. 

History. — This  urchin  was  figiu-ed  and  described  for  the  first  time  by  Goldfuss,  from 
some  isolated  plates  and  spines  collected  from  the  creta  margacea  of  Westphalia;  that 
author  cites,  as  identical  with  Cidaris  vesiculosa,  a  fragment  from  the  White  Chalk  of 
England  figured  by  Parkinson,  but  which  belongs  to  another  species,  probably  Cid. 
perornata,  Eorb.  This  error  has  led  to  much  confusion,  for  we  find  Cid.  vesiculosa,  Goldf., 
cited  in  many  English  lists  as  having  been  obtained  from  the  White  Chalk  of  Kent,  Sussex, 
and  Wilts ;  whereas  the  new  form  now  figured  and  identified  with  Goldfuss's  species  has 


FROM  THE  GREY  CHALK.  45 

been  collected  only  from  the  Gray  Chalk  of  Dover  and  the  Upper  Greensand  of  Wilts. 
Cidaris  vesiculosa,  Forbes,  is  a  very  different  form  from  the  true  C.  vesiculosa,  Goldf. ;  and  1 
must  refer  the  reader  to  the  article  on  that  species  for  more  ample  details.  This  species 
has  been  beautifully  figured  and  well  described  by  M.  Cotteau,  both  in  his  Monograph  on 
the  Echinidee  of  Sarthe,  and  his  continuation  of  D'Orbigny's  Echinides  de  Terrains 
Cretaces,  in  the  Paleontologie  Fran9aise,  a  vi^ork  which  has  profited  so  much  by  M.  Cot- 
teau's  extensive  knowledge  of  this  subject.  This  species  has  now  been  identified  and 
figm'ed  as  British  for  the  first  time. 


CiDARis  BowERBANKii,  Forbcs.     PI.  II,  fig.  1,  a — d. 

Cidaris  Bowerbankii,  Forbes,  in  Dixon's  Geol.  and  Fossils  of  Sussex,  pi.  xxix,  fig.  4, 

p.  330,  1850. 
—  —  Forbes,  in  Morris's  Cat.  of  Brit.  Foss.,  2nd  ed.  p.  74. 

Test  spheroidal,  depressed,  ambulacra!  areas  with  four  or  six  rows  of  nearly  equal- 
sized  granules  ;  inter-ambulacral  areas  wide,  five  or  six  large  spinigerous  tubercles,  with 
small  areolae  in  each  column ;  miliary  zone  wide,  filled  with  small,  close-set, 
equal-sized  granules.  Spines  very  large,  thick,  and  inversely  conical,  stems  short,  the 
surface  covered  with  irregular,  longitudinal  rows  of  granulated  spines. 

Dimensions. — Transverse  diameter  one  inch ;  height  unknown. 

Description. — The  body  of  this  Cidaris,  which  is  very  nearly  allied  to  C.  clavigera,  is 
more  compressed  above  and  below  than  in  that  species. 

The  ambulacral  areas  are  occupied  by  four  or  six  small,  nearly  equal,  granular 
tubercles  in  each  transverse  row,  and  the  poriferous  zones  are  narrow  and  slightly 
sinuous. 

The  inter-ambulacral  areas  are  wide  ;  the  spinigerous  tubercles,  five  or  six  in  each 
column,  have  small  areolae,  without  prominent  margins ;  the  miliary  zone  is  flat,  and 
undepressed ;  and  the  entire  surface  is  thickly  covered  with  minute  nearly  equal-sized 
granules,  of  which  a  circle  of  larger  ones  surround  the  border  of  the  areolae. 

The  primary  spines,  seen  in  situ  on  the  test  (fig.  1,  a),  are  thick,  almond- 
shaped,  inversely  conical  bodies,  with  a  shoi-t  neck,  into  which  the  body  suddenly 
contracts  (fig.  \,  b) ;  the  milled  ring  is  broad  and  prominent  (fig.  1,  c),  and  the  acetabulum 
has  a  narrow  rim  close  to  the  ring ;  the  surface  is  minutely  granulated  with  small  spinous 
points,  arranged  in  regular  longitudinal  rows  (fig.  \,b);  the  spines  which  clothe  the 
granular  tubercles  are  small,  compressed,  conical  bodies,  with  a  striated  surface  (fig.  \,d); 
several  of  these  are  found  in  situ  on  the  plates  of  the  test. 


46  CIDARIS 

Affinities  and  differences, — This  species  most  nearly  resembles  C.  davigcra,  Kouig ;  it 
is  distinguished  fiom  that  species,  according  to  Professor  Forbes,  by  having  "  the  ambulacral 
segments  slightly  broader  in  proportion  to  the  inter-ambulacrals,  and  instead  of  their 
breadth  being  occupied  by  transverse  series  of  about  four  granular  tubercles,  two  of  which 
are  very  small  and  inconspicuous,  there  are  four,  or,  centrally,  even  six,  nearly  equal 
granular  tubercles  in  each  transverse  row.  The  large  spinigerous  tubercles  of  the  ambu- 
lacral plates  are  placed  in  areolae,  much  smaller  in  proportion  to  the  entire  body  than  in 
C.  clavigera,  and  the  tubercles  themselves  are  also  smaller.  The  spaces  between  the 
rows  of  spinigerous  tubercles  are  wider ;  they  are  thickly  studded  with  nearly  equal 
granules." 

The  spines  of  C.  Bowerhankii  resemble  those  of  C.  clavigera ;  but  the  club-shaped 
head  occupies  the  entire  stem  in  the  former,  whereas  in  C.  clavigera  the  club-shaped  head 
is  carried  on  the  long  stem.     Compare  PI.  II,  fig.  1,  with  PL  IV,  fig.  1 — 3. 

Localitg  and  Stratigraphical  Position. — This  species  has  been  found  only  in  the  Gray 
Chalk  of  Dover.  The  fine  specimen  I  have  figured  is  unique,  and  belongs  to  the 
cabinet  of  our  kind  friend  Dr.  Sowerbank,  F.R.S. 

Eistory. — First  figured  by  Prof.  Forbes,  in  Dixon's  '  Geology  and  Fossils  of  Sussex,' 
■who  likewise  established  the  species  in  that  work.  The  same  specimen  has  been  kindly 
lent  by  Dr.  Bowerbauk  to  figure  in  this  Monograph. 

CiDARis  DissijiiLis,  Forbes.     PI.  Ill,  III  a,  figs.  1  and  2. 

CiUAEis  scEPTRiFERA,  Forbes,  in  Dixon's  Geology  of  Sussex,  pi.  xxv,  fig.  3. 

—  DissiMiLis,      Forbes,  iu  Morris's  Cat.  of  Brit.  Fossils,  2ud  ed.,  p.  74. 

—  —  Woodward.     Mem.  Geol.  Survey,  Decade  v,  e.vpl.  pi.  v. 

Test  small,  depressed,  ambulacral  areas  narrow,  flexuous,  with  six  rows  of  small 
granules ;  inter-ambulacral  plates,  four  to  five  in  a  column ;  areolae  circular,  wide  apart, 
surrounded  by  distinct  secondary  tubercles ;  principal  tubercles  prominent,  bosses  slightly 
crenulated,  the  inferior  oral  tubercles  minute,  the  uppermost  discal,  rudimentary,  and 
without  areolae ;  miliary  granules  large  and  prominent ;  spines  slightly  fusiform,  surface 
covered  with  longitudinal  lines  of  prickles. 

Dimensions. — A.  Transverse  diameter  eleven  lines ;  height  six  and  a  half  lines. 
B.  Transverse  diameter,  one  and  one  fifth  inches. 

Description. — This  urchin  resembles  Cidaris  sceptrifera  in  its  general  characters,  but 
was  separated  from  that  species  by  Professor  Forbes  in  his  MS.  notes   on  this  Cidaris. 


FROM  THE  GREY  CHALK.  47 

The  test  is  small  and  depressed  at  both  poles ;  the  arabulacral  areas  are  narrow,  with  six 
rows  of  granules  at  the  equator,  diminishing  to  two  rows  at  the  discal  and  oral  apertures 
(PI.  Ill  a,  fig.  2,  c). 

The  inter-ambulacral  areas  are  wide,  and  the  plates  large,  from  four  to  five  in  a  column  . 
the  areolae  are  circular  and  wide  apart,  the  margins  prominent,  and  surrounded  by 
distinct  secondary  tubercles ;  the  boss  is  prominent  and  slightly  granulated ;  the  tubercle 
is  moderate  in  size  and  perforated ;  the  tubercles  near  the  peristome  are  small  (fig.  2,  b), 
and  those  nearest  the  apical  disc  rudimentary  (fig.  2,  a),  and  destitute  of  true  areolae 
(fig.  2,  c). 

The  miliary  zone  is  wide  and  zig-zag,  aud  covered  with  large  prominent  granules 
(fig.  2  c),  among  which  smaller  granules  are  irregularly  strewed. 

I  have  given  in  fig.  1  a  a  drawing  of  the  fine  specimen  of  this  species  from  the  late 
Mr.  Taylor's  collection,  now  in  the  British  Museum,  and  in  fig.  2,  a,  b,  a  larger  specimen 
from  the  cabinet  of  the  Rev.  T.  Wiltshire,  F.G.S. 

The  spines,  according  to  Mr.  S.  P.  Woodward,  are  of  two  kinds,  "  the  largest  above 
twenty-four  lines  in  length,  slightly  swelling  above  the  collar  (two  and  a  half  lines  in 
diameter),  and  then  tapering  to  a  fine  point ;  collar  short,  striated  finely ;  shaft  granulated 
in  hues ;  spines  of  the  lower  surface  very  slender,  three-  to  six-sided,  serrated  at  the 
angles ;  spines  of  the  areolar  circles  two  lines  in  length,  compressed  and  striated." 

Fig.  1,  5,  is  a  spine  of  C.  dissimilis  belonging  to  the  British  Museum. 

Fig.  2,  d,  e,f,  are  spines  from  the  collection  of  the  Rev.  T.  Wiltshire. 

Affinities  and  Differences. — This  urchin  so  closely  resembles  C.  sceptrifera  that  it  was 
identified  as  such  by  Professor  Forbes  in  Dixon's  Geology  of  Sussex ;  in  his  manuscript 
notes  on  more  perfect  examples  he  had  separated  it  under  the  name  C.  dissimilis.  All 
the  best  specimens  known  to  me  I  have  figured  in  PI.  Ill  a. 

Locality  and  Stratigrapliical  Position. — This  species  was  collected  by  Messrs.  Clarke, 
Dixon,  Taylor,  and  the  Rev.  T.  Wiltshire,  from  the  Gray  Chalk  at  Dover ;  the  finest  of 
these  specimens  I  have  now  figured  for  the  first  time.  Fig.  \,  a,  b,  belonged  to  the 
late  Mr.  Taylor's  collection,  and  is  now  in  the  British  Museum.  Fig.  2,  a,  b,f,  and  figs. 
3  to  5,  belong  to  the  Rev.  T.  Wiltshire's  cabinet. 

History. — This  Cidaris  was  referred  to  C.  sceptrifera  by  Professor  Forbes  in  his 
description  of  that  species  in  Dixon's  Geology  of  Sussex.  The  subsequent  discovery  of 
more  perfect  specimens  induced  him  to  separate  it  from  that  fomi  under  the  name  of 
C.  dissimilis  in  the  MS.  notes  he  left  on  the  Cretaceous  urchins. 


CIDARIS 


CLAVIGERA, 


. —      PiiOFiNQUA  (pars) 

CLAVIGERA, 


D. — Species  from  the  White  Chalk. 

Cll>AKIS  CI-AVIGEKA,   Kd)U(/.       PI.   IV,  PI.  V,  figS.   1 15. 

Be  Luc.     Jlem.  siir  un  Echinide  singnlicr  Mem.  Acad. 

Roy.  des  Sciences,  t.  ix,  p.  467,  pi.  xii,  1763. 
Andrea,  J.  G.  R.     Briefe  aus  der  Schweiz  nach  Han- 
nover Geschr.  in  dem  Jahr.,  1763. 
CiDAKis  PAPILLATA,  vor.  Leslie.     Klein,  Nat.  disp.  Eclunoderm,  p.  134,  pi.  xlvi, 

figs.  2  and  3. 

—  spiNis  C1.AVICULAT1S,  Parhinson.     Organic  Remains,  t.  iii,  pi.  iv,  figs.  1  and 

21,  1811. 
Konig,  in   Mantell's   Geo),   of  Sussex,   p.  194,   pi.  xvii, 

figs.  11  and  14,  1822. 
Konig.     Icoues  Fossilium  Sectiles,  1825. 
Agassi:.     Prod.  Mem.  Soc.  des  Sc.  Nat.  de  Neuchatel, 

t.  i,  p.  188,  1836. 
Besmoulins.     Etudes  sur  les  Echinides,  p.  383,  No.  34, 

1837. 
Besmoulins.     Ibid.,  p.  332,  No.  22,  1837. 
Geinite.     Charakter  der    Schict.    und    Petref.    Kreide- 

gebirges,  p.  90,  1839. 

—  —  Agassiz.     Catal.  Syst.  Foss.,  p.  10,  1840. 

—  —  Hisinger.     Lethsea  Suecica,  pi.  xxvi,  figs.  5,  6,  1840. 

—  —  Roeiner.     Norddeutschen  Kreidegebirges,  p.  28,  pi.  vi, 

fig.  7,  1840. 

—  —    •  Morris.     Cat.  of  Brit.  Fossils.,  p.  49,  1843. 

—  —  Agassi:  et  Besor.     Cat.   rais.   des  £ch.  Ann.   Sc.  Nat., 

3e  serie,  t.  vi,  fig.  327,  1846. 

—  —  Rettss.     Versteinerungen  der  Bohmischen    Kreideform., 

p.  57,  pi.  XX,  figs.  17—20,  1846. 

—  —  Graves.     Essai   sur  la   top.  Ge'og.    du   dep.    de   I'Oise, 

p.  692,  1847. 

—  —  Bronn.     Index  Paleeontologicus,  p.  298,  1848. 

—  —  B^Orhigny.     Prodrome  de  Paleont.,  t.  ii,  p.  273,  Et.  22, 

No.  1246,  1850. 

—  —  Sorignet.     Ours,  de  I'Eure,  p.  1,  1850. 

—  —  Forbes,  in  Dixon,  Geol.  of  Sussex,  p.  338,  pi.  xxv,  figs. 

10,  11,  14,  18,  19,  20,  1852. 

—  Quenstedt.     Handbuch  der  Petrefackt.,  p.  575,  pi.  xlviii, 

fig.  46,  1852. 
—  Forbes,  in  Morris's  Cat.  of  Brit.  Fossils,  2nd  ed.,  p.  74, 

1855. 
—  Besor.     Synopsis  des  Echinides  Fossiles,  p.  12,  pi.  vi, 

fig.  15,  1855. 

—  Hf.berti,  Besor.     Ibid.,  p.  12,  1855. 


FROM  THE  WHITE  CHALK.  49; 

CiDARis  CLAVIGEEA,  Fictet.     Traite    de    Paleoiitol.,    2nJ   ed.,  t.   iv,  p.  254, 

pi.  xcviii,  fig.  8,  1857. 

—  —  Cotfeau.     Palcontologie  FMD^aise ;  Ter.   Cretac^,  t.  vii, 

pi.  I06y,  1070,  1071,  p.  285,  1862. 

—  —  Dujardin  et  Hup^.      Hist.  Nat.  des  Zooph. ;    Echino- 

dermee,  p.  480,  1862. 

—  Heberti,  Bujardin  et  Ilupe.     Ibid. 

Tfest  circular,  moderately  inflated,  of  medium  size,  and  nearly  equally  depressed  at 
both  poles.  Ambulacral  areas  narrow,  slightly  flexed,  with  four  rows  of  mammillated 
granules,  the  inner  being  smaller  than  the  outer  rows ;  inter-ambulacral  areas  wide, 
five  very  large  tubercles  in  each  row ;  nreote  deep,  circular,  and  complete ;  margin 
surrounded  by  a  circle  of  mammillated  granules;  tubercles  large  and  imperforate,  boss 
.smooth ;  miliary  zone  wide,  not  depressed,  fiirnislied  with  large  granules ;  peristome 
small,  subpentagonal ;  apical  disc  large,  subcircular ;  spines  large,  clavate,  crowded  with 
longitudinal,  prickly  ribs. 

Dimensions. — Transverse  diameter,  one  inch  and  three  tenths ;  height,  seven  tenths 
of  an  inch. 

Description. — The  finest  examples  of  this  urcliin  extant  arc  those  now  figured  in 
Plates  IV  and  V,  the  one  belonging  to  my  friend.  Dr.  J.  S.  Cowerbank,  PI.  IV,  the 
other  to  the  British  Museum,  PI.  V,  fig.  1  ;  both  these  specimens  were  collected  and 
developed  by  the  late  Mr.  Taylor,  and  formed  part  of  his  collection  of  CretaceoUs  Echino- 
dermata.  Having  had  abundant  materials  at  my  disposal  for  the  illustration  of  this  species, 
I  have  endeavoured  to  give  accurate  figures  of  all  parts  of  the  test,  as  well  as  of  the 
remarkable  spines  which  armed  it.  An  examination  of  the  series  I  have  figured  will 
show  how  very  much  the  spines,  from  difiierent  parts  of  the  test,  differ  from  each,  and  how 
cautious  we  ought  to  be  in  founding  species  of  Cidaris  on  the  spines  alone. 

The  test  is  of  medium  size,  circular,  moderately  inflated,  and  nearly  eqxially  depressed 
at  both  poles.  The  ambulacral  areas  are  narrow,  sliglitly  flexed,  and  provided  with  four 
rows  of  granules  ;  the  external  are  the  largest,  and  most  regular,  and  are  elevated  on 
mammillated  summits  close  to  the  border  of  the  poriferous  zones;  the  internal  rows  are 
composed  of  smaller  granules,  irregular  in  size,  arrangement,  and  extent ;  towards  the 
ends  of  the  areas  they  diminish  in  size,  and  gradually  disappear  whilst  the  external 
rows  are  persistent  throughout.  A  number  of  microscopic  granules  are  irregularly 
scattered  among  the  internal  rows,  and  form  a  regular  series  at  the  angle  of  the  external 
granules,  on  the  border  of  the  poriferous  zones,  and  opposite  each  pair  of  holes. 

The  poriferous  zones  are  narrow,  depressed,  and  slightly  flexed  ;  the  pores  are  large, 
round,  and  open,  closely  approximated  to  each  other,  and  having  small  elevated  granules 
on  the  septa  (PI.  IV,  fig.  I,  b). 

7 


50  CIDARIS 

The  inter-ambiilacral  areas  are  wide  (PI.  IV,  fig.  1 ;  PI.  V,  fig.  2,  a,  b),  Avith  five  very 
large,  prominent  tubercles  in  each  row;  the  areolas  are  narrow,  deep,  and  circular,  closely 
approximated  near  the  peristome  (PI.  V,  fig.  2,  b),  and  wide  apart  at  the  upper  surface 
(PI.  V,  fig.  2,  a) ;  the  margin  is  surrounded  by  a  circle  of  small  mammillated  granules 
(PI.  IV",  fig.  1 ,  b,  c),  a  little  larger  than  those  which  fill  the  miliary  zone ;  the  boss  is 
small,  and  not  prominent,  and  its  summit  quite  smooth  (PI.  IV,  fig.  b,  c) ;  the  tubercle 
is  very  large  and  prominent  (PI.  V,  fig.  2 ;  and  PI.  IV,  fig.  \,b,  c);\i  forms  three  fourths 
of  a  sphere,  and  the  surface  is  imperforate ;  the  tubercle  nearest  the  disc  is  sometimes 
surrounded  by  a  rudimentary  areola  (PI.  IV,  fig.  1,  a ;  PI.  V,  fig.  2,  a),  and  placed 
wide  apart  from  its  penultimate  fellow.  The  areolas  at  the  under  surface  are  so  closely 
approximated  that  many  of  them  are  separated  only  by  a  single  row  of  granules. 

The  apical  disc  (PI.  V,  fig.  3)  is  wider  in  diameter  than  the  peristome  ;  the  five  ocular 
plates  are  large,  with  prominent  orbits  surrounded  by  a  radiated  structure;  the  ovarial 
plates  have  a  rhomboidal  figure,  with  the  hole  distant  from  the  border ;  the  anal  plates 
are  well  preserved  in  the  specimen  fig.  3,  in  which  sixteen  plates  remain  i7i  situ;  the 
surface  of  all  the  elements  of  the  disc  is  covered  with  small  granules,  set  well  apart  from 
each  other;  fig.  3  shows  the  disc  and  its  elements  magnified  two  and  a  half  times. 

The  jaws  and  teeth  are  in  situ  in  the  specimen  belonging  to  the  British  Museum 
(PI.  V,  fig.  1)  ;  the  peristome  is  small  (fig.  2,  b) ;  and  more  than  half  the  opening  was 
filled  by  a  buccal  membrane,  on  which  two  or  three  rows  of  scale-like  plates  are  disposed 
in  an  imbricated  manner.  PI.  V,  fig.  4,  exhibits  the  buccal  membrane  and  its  plates 
magnified  two  and  a  half  times. 

The  form  of  the  spines  varies  in  different  parts  of  the  test.  In  general  they  are 
claviform,  more  or  less  developed,  with  massive  bodies,  elongated  necks,  and  small 
articular  heads.  The  body  and  neck  are  ornamented  with  numerous  longitudinal  ridges  ; 
those  on  the  massive  body  develope  a  denticulated,  spiny  margin,  as  seen  in  PL  IV,  fig.  5, 
and  in  other  series  of  spines  figured  in  this  jjlate.  The  denticulated  ridges  are  sometimes 
prominent  and  regular,  unequal,  oblique,  and  rudimentary ;  on  the  neck  the  ridges  are  in 
general  smaller,  longitudinal,  and  with  finer  denticulations  on  the  margin ;  at  the  inferior 
third  of  the  neck  they  diminish  in  size  and  disappear,  and  are  replaced  by  granules,  which 
likewise  fill  up  all  the  intermediate  space  between  the  ridges,  both  on  the  neck  and 
massive  head.  In  some  spines,  with  a  large  head  and  short  neck,  the  weight  of  the 
spine  is  diminished  by  a  series  of  canals,  which  extend  into  the  head  beneath  the  spaces 
between  the  ridges;  the  head  is  sometimes  traversed  by  a  large  channel,  opening  at  the 
sumn)it,  as  in  a  specimen  (PI.  V,  fig.  G)  from  the  Eev.  T.  Wiltshire's  collection.  The 
collar  is  very  small,  and  finely  striated ;  the  milled  ring  is  narrow,  and  separated  from  the 
collar  by  a  depression  ;  both  ring  and  depression  being  finely  milled  ;  the  acetabulum  (fig. 
2)  is  moderately  deep,  with  a  well-defined  ring  round  the  margin.  In  Plate  IV,  I  have 
figured  the  finest  specimen  extant  of  this  species ;  it  belongs  to  my  friend  Dr.  Bowerbank, 
and  shews  two  tests  with  their  spines  attached  in  situ.    This  specimen  exhibits  the  various 


FROM  THE  WHITE  CHALK.  51 

forms  of  the  spines  in  different  regions  of  the  shell,  and  the  series  of  figures  between 
3  and  23  shows  some  of  the  extreme  shapes  these  appendages  assume. 

Affinities  and  Differences. — This  urchin  is  readily  distinguished  from  other  species  of  the 
White  Chalk  by  its  small  test,  equally  depressed  at  both  poles,  narrow  areolae,  prominent 
imperforate  tubercles,  and  large  claviform  spines,  more  or  less  elongated,  and  covered  with 
spinous  ridges.  In  this  respect  it  resembles  C.  Bowerbankii,  Forb.,  PI.  II,  fig.  1,  from 
which  it  is  distinguished  chiefly  by  the  character  of  the  spines,  and  the  larger  size  of  the 
inter-ambulacral  tubercles.     Compare  PI.  II,  fig.  1,  a,  with  PI.  IV,  fig.  1. 

LocaJity  a7id  Sfrafiyrapliical  Position. — This  is  the  most  common  Cidaris  in  our 
White  Chalk  ;  it  is  found  at  Woolwich,  Gravesend,  Lewes,  Brighton,  and  in  the  same 
formation  in  Wilts  and  Dorset.  The  specimens  figured  in  Pis.  IV  and  V  were  found 
near  Woolwich,  and  developed  by  the  late  Mr.  Taylor.  The  grand  s[)ecimen  figured  in 
PI.  IV  is  in  the  possession  of  Dr.  Bowerbank,  that  in  PI.  V,  showing  the  dental  apparatus, 
peristomal  plates,  and  apical  disc,  belongs  to  the  British  Museum. 

It  is  very  abundant  in  the  Etage  Senonien  of  France,  and  found,  according  to  M. 
Cotteau,  at  Dieppe,  Fecamp,  Tancarville  (Seine-Inferieure) ;  Falaise  (Somme) ;  Vernonnet, 
Giverny,  Clachaloze,  Petit-Andelys,  Pinterville  pres  Louviers,  Hougue-marre,  Sinneville 
(Eure) ;  Notre-Dame-du-Thil,  Mory  la  Herelle,  le  Mesnil-Saint-Fermin,  Pouilly  La- 
boissiere  (Oise)  ;  Maintenon,  Chateau- GaiUard  (Seine-et-Oise)  ;  le  Mesnil-Saint-Thomas 
(la  Poterie)  (Eure-et-Loire). 

History. — This  urchin  was  first  figured  and  described  by  De  Luc  in  1763,  and  after- 
veards  by  Leskeand  Parkinson  ;  in  1823  by  Mr.  Koenig,  in  Mantell's  '  Geology  of  Sussex,' 
who  named  it  C.  davigera.  The  first  accurate  description  of  the  test  and  spines  was  made 
by  M.  I'Abbe  Sorignet,  who  pointed  out  the  size  and  imperforation  of  its  tubercles  as 
important  diagnostic  characters.  It  has  recently  been  well  figured  by  M.  Humbert  for 
M.  Cotteau  in  the  '  Paleontologie  Fran9aise  ;'  and  Mr.  Bone  has  given  most  ample  details 
from  all  the  best  English  specimens  that  I  am  acquainted  with. 

Cidaris  serrifkra,  Forbes,  1850.     PI.  XI,  fig.  1,  a,  b,  c,  d,  e,/,  r/,  h,  fig.  6. 

CiDAius  CLAVIGERA,    Revss.     Versteinerungeii   der  Bohmischen  Kreidef.,    p.   57,   pi. 
x.\,  fig.  21,  1845. 

—  SEiiRirERA,     Forbes,  in   Dixon's  Geo),  and  Foss.  of  Sussex,  p.  338,  pi.  xxiv, 

figs,  15  —  19,  and  pi.  xxv,  fig.  2,  1850. 

—  PUNCTILLUM,  Sorignet.     Oursins  Foss.  de  I'Etire,  p.  9,  1850. 

—  SEKEIFERA,     Forbes,  in  Morris's  Cat.  of  Brit.  Foss.,  2nd  ed.,  p.  75,  1854. 

—  PUNCTILLUM,  Desor.     Synopsis  des  Echinides  Foss.,  p.  15,  1856. 

—  —  lhijari/i?i  et  Hup^,  Zoophytes  ;  fichinodermes,  p.  481,  1862. 

—  SEKRTFERA,     Cotteau.     Paleontologie   Fran9ai8e  ;  Ter.  Cret.  ;  Ecbinides,  torn. 

ii,  p.  293,  pi.  1071,  figs.  5—15,  1863. 


52  CIDARIS 

Test  small,  circular,  convex  above,  flat  below,  poriferous  zones  narrow,  depressed, 
slightly  flexed,  pores  oval,  approximated,  separated  by  a  small  granule  ;  ambulacral  areas 
sinuous  and  depressed  in  the  middle,  with  from  six  to  eight  rows  of  small,  round  granules  ; 
inter-ambulacral  areas  wide  and  inflated  above,  with  four  to  five  small  perforated  tubercles 
in  each  row,  placed  wide  apart,  with  a  miliary  zone  between  them ;  spines  long,  slender, 
cvlindrical,  covered  with  longitudinal,  compressed,  spiny  ribs,  having  a  wide  valley  and 
uranulated  surface  between  them. 

Dimensions. — Transverse  diameter,  one  inch  and  one  sixth;  height,  six  tenths  of 
an  inch. 

Description. — '^I'his  beautiful  urchin  was  distinguished  by  Professor  Forbes  from 
C.  clavigera,  for  which  it  had  been  mistaken  by  Reuss,  and  was  first  figured  in  Dixon's 
'  Geology  of  Sussex;'  it  forms  a  well-marked  species,  which  is  very  rare  in  our  Cretaceous 
rocks.  The  test  is  small,  and  circular ;  inflated  at  the  equator  and  upper  surface,  and 
flattened  below;  the  poriferous  zones  are  slightly  flexed,  narrow,  and  depressed;  the  pores 
are  small,  oval,  and  approximated ;  there  is  a  granule  between  them  on  the  septum  ;  and 
an  oblong  transverse  ridge  between  each  pair.  The  ambulacral  areas  are  narrow,  and 
slightly  undulated  ;  the  plates  incline  gently  towards  the  median  suture,  and  are  provided 
with  from  four  to  six  rows  of  small,  close-set  granules,  of  which  the  external  rows  are  the 
largest,  and  raised  on  mammillated  eminences ;  the  smaller  and  shorter  middle  rows 
disappear  near  the  disc  and  the  peristome,  where  there  are  only  the  two  external  rows 
of  mammillated  granules ;  there  are  from  fifteen  to  seventeen  files  of  granules  opposite 
one  of  the  large  plates.  The  wide  inter-ambulacral  areas  are  slightly  inflated  above  and 
near  the  equator,  and  have  from  four  to  five  deep  plates  in  each  series ;  the  areolae  are 
small,  and  gradually  increase  in  diameter  from  the  peristome  to  the  uppermost  tubercle ; 
on  the  uppermost  plate  of  each  alternate  series  the  tubercle  is  nearly  obsolete ;  the  border 
of  the  areola  is  a  little  elevated,  and  surrounded  by  a  circle  of  small,  spaced-out,  mammil- 
lated granules  (fig.  1,  d),  a  little  larger  than  those  which  fill  the  miliary  zone;  the  boss 
is  small,  the  summit  smooth,  and  the  tubercle  perforated  in  all  the  specimens  I  have 
seen  ;  the  inter-tubercular  spaces  and  central  miliary  zone  are  filled  with  a  fine,  uniform, 
close-set  granulation ;  on  the  upper  part  of  the  shell  the  tubercles  nearest  the  disc  are 
small,  imperfectly  developed,  and  surrounded  by  the  merest  trace  of  an  areola;  the 
sutures  of  the  plates  are  depressed  and  conspicuous;  the  peristome  (fig.  \,h)vi  small, 
circular  or  subpentagonal ;  the  discal  opening  is  larger  than  the  peristome,  and  sub- 
pentagonal  ;  a  portion  of  the  disc,  concealed  in  the  specimen  (fig.  1,  a),  exhibits  a  finely 
granulated  surface. 

In  a  fossil  I  collected  twenty  years  ago  at  Lewes,  in  Sussex,  many  of  the  spines 
are  preserved  in  situ  on  the  fragment  of  the  test  (fig.  1,  e,f,g)\  they  aie  long,  slender, 
and  cylindrical,  having  seven  or  eight  compressed  ridges,  with  a  denticulated  border;  the 


FROM  THE  WHITE  CHALK  .  53 

valleys  between  the  ridges  are  concave,  and  the  surface  of  these  is  very  finely  granulated ; 
the  neck  is  long  and  smooth  (fig.  1,/,  and  fig.  2);  it  is  bounded  by  a  fine  line,  and 
beyond  this  is  a  narrow  circle  with  microscopic  lines  conducting  to  a  milled  ring,  which  is 
prominent  and  finely  sculptured  (fig.  \,f,  and  fig.  2);  the  head  is  small,  and  the  rim  of 
the  acetabulum  striated;  the  small  secondary  spines  are  flat  and  conical  (fig.  1,  li),  and 
have  the  surface  ornamented  with  fine  longitudinal  lines. 

Affinities  and  Differences. — This  species  is  allied  to  Cidaris  vesiculosa,  Goldfuss,  but 
distinguished  from  that  form  by  having  the  test  more  regularly  convex,  the  plates  of 
the  inter-ambulacra  less  inflated,  and  fewer  tubercles  in  each  series.  The  spines  of  the 
two  species  are  likewise  different.  It  resembles  Cidaris  sceptrifera,  Mantell,  but  has  smaller 
areolas,  less  prominent  scrobicular  circles,  fewer  tubercles  in  each  column  of  plates  ;  and  the 
spines  are  very  distinct  (compare  for  example  PI.  VII,  fig.  1,  with  PI.  XI,  fig.  1 ).  According 
to  Professor  Forbes,  it  differs  from  Cidaris  snhvesicuhsa,  d'Orbigny,  in  having  the  inter- 
ambulacra  composed  of  large  plates  with  impressed  areolae  around  the  spiniferous 
tubercles,  four  to  six  in  the  perpendicular  row.  Tubercles  larger  in  proportion  to  the 
areolae  than  in  the  last  species.  Superior  plates  with  indistinct  tubercles,  but  not  so 
obsolete  as  in  C.  subvesicidosa.  Granulated  portion  of  the  plates  finely  grained ;  the 
sutures  are  not  impressed ;  the  avenues  of  pores,  of  which  about  fourteen  correspond  to 
the  largest  plate,  are  broader  in  proportion  to  the  ambulacra.  There  is  a  tubercle 
between  each  pore,  and  an  oblong  transverse  ridge  between  each  pair. 

Locality  and  Stratigraphical  Position. — I  collected,  about  twenty  years  ago,  a 
specimen  of  this  urchin  with  the  spines  attached  to  the  test,  in  the  Upper  Chalk,  at  Lewes, 
in  Sussex ;  the  example  of  this  species  figured  in  Dixon's  work  was  obtained  from  the 
same  locality.  The  fine  fossil  which  I  have  figured  in  PI.  XI,  fig.  1,  was  kindly  com- 
municated for  this  Monograph  by  Henry  Willett,Esq.,F.G.S.,  Brighton.  This  specimen 
appears  to  be  the  original  fossil  which  was  figured  before  by  Sowerby  in  Dixon's  '  Geology 
of  Sussex  ;'  if  so,  it  formed  the  subject  of  Professor  Forbes'  observations. 

In  France  this  urchin  is  very  rare ;  it  was  found  in  the  Etage  Senonien  at  Civieres, 
Giverny  (Eure) ;    Royan  (Charente-Inferieure). 

History. — This  species  was  first  well  figured  as  Cidaris  serrifera  by  Professor  Forbes 
in  Dixon's  '  Geology  of  Sussex'  in  1850.  The  same  year  M.  I'Abbe  Sorignet  described 
it  under  the  name  C.  punctillum  in  his  work  on  the  Fossil  Urchins  of  the  Department  of 
the  Eure  ;  as  this  account  was  not  accompanied  by  a  figure,  I  have  retained  the  name 
of  the  figured  specimen.  In  184. "3,  Prof.  Reuss  figured  this  Cidaris  in  liis  fine  work  on 
the  Fossils  of  the  Bohemian  Chalk-formation,  and  erroneously  referred  it  to  Cidaris 
claviyera,  Konig,  from  which  it  differs  in  many  important  details  both  in  the  structure 
of  the  test  and  spines. 


54 


CIDARIS 


CiDARis    scEPTRiFERA,   Muntell.     PI.  V,  figs.    16,  17;    PI.  VI;    PI.  VII,  figs.  1,  2;  PI. 

VII  a,  figs.  1,  3. 


CiDAKIS  CUCUMERINA, 
—        SCEPTRIFERA, 


—  CRETOSA, 

—  VESICULOSA, 

—  SCEPTRIFERA, 


Parkinson.     Organic  Remains,  vol.  iii,  pi.  iv,  fig.  2,  1811. 
Mantell.     Geol.  of  Sussex,  p.  194,  pi.  xvii,  fig.  12  (spine), 

1822. 
Agassiz.     Catal.  Syst.  Ectyp.  Foss.,  p.  10,  1840. 
Ranter.     Norddfiitscheu  Kreidegebirge,  p.  28,  1840. 
Morris.     Catalogue  of  Brit.  Foss.,  p.  49,  1843. 
Agassis   et  Desor.     Catal.  rais.  des  Echinides  ;  Ann.   Sc. 

Nat.,  3e  ser.,  t.  vi,  p.  328,  1846. 
Renss,  pars.     Versteinerungen  der  Bohmisclien    Kreidefor- 

nialion,  p.  57,  pi.  x.t,  fig.  15,  1846. 
Graves.     Essai  sur   la   Topogr.    Geo),    dii    Dep.   de   I'Oise, 

p.  688,  1847. 

—  —  Bronn.     Index  Palaeontologicus,  p.  298,  1848. 

—  —  d'Orbigny.     Prod,  de  Pal.  Strat.,  t.  ii,  p.  2/4,  1850 

—  —  Sorignet.     Ours,  de  I'Eure,  p.  6,  1850. 

—  —  Forbes,  in  Dixon,  Geol.  of  Sussex,  p.  338,  pi.  xxv,  figs.  3 — 7, 

1850. 

—  —  Forbes,  in  Morris,  Catal.  of  Brit.  Foss.,  2nd  edit.,  p.  74,  1854. 

—  —  Desor.     Synopsis  des   Echinides  Foss.,  p.  13,  pi.  v,  fig.  28, 

1855. 

—  —  Woodward.     Mem.  of  the  Geol.   Survey,  Dec.  v,  expl.  to 

pi.  V,  fig.  12,  1856. 

—  —  Leymerie  et  Raulin.     Stat.    Geol.    dii   Depart,   de   TYoune, 

pp.  510—620,  1858. 

—  —  Coquand.     Synops.   des    Foss.  Form.  Cret.  du  Sud-Ouest  de 

la    France;    Bull.   See.   Geol.,    2e   ser.,    t.  xvi,    p.    1013, 
1860. 

—  —  Cotteau  et  Triger.     Ech.  du   Dep.    de  la    Sarthe,    p.  253, 

pi.  xlii,  figs.  1—8,  1860. 

—  —  Cotteau.     Paleont.    Fran9aise,    p.    251,    pi.    1056-57-58, 

1863. 

—  —  HupL     Hist.  Nat.  Zooph. ;  Eehinoderraes,  p.  480,  1862. 

Test  moderately  large  and  inflated ;  more  or  less  elevated,  and  nearly  equally  flattened 
at  both  poles ;  ambulacral  areas  narrow,  depressed,  flexuous,  with  six  rows  of  grannies  in 
the  middle,  diminishing  to  four  rows  above  and  below ;  poriferous  zones  narrow,  winding, 
and  depressed  ;  inter-ambnlacral  areas  wide ;  plates  very  large,  five  to  six  in  a  column ; 
areolae  deep,  circular,  with  an  elevated,  prominent,  scrobicular  margin,  encircled  by  a 
series  of  small  granules,  scarcely  larger  than  those  of  the  miliary  zone ;  boss  not  prominent, 
summit  feebly  crenulated  in  young,  and  smooth  in  old  shells;  tubercle  moderate  in  size 
and  perforated  ;  proximal  discal  plate  in  each  column  with  a  rudimentary  tubercle,  and  an 
elongated    obsolete    areola;   miliary   zone  filled    with  small,  equal-sized  granules,  much 


FROM  THE  WHITE  CHALK.  55 

depressed  along  the  line  of  all  the  sutures ;  apical  disc  wide ;  ovarial  plates  thick,  large ; 
ocular  plates  heart-shaped  ;  spines  long,  cylindrical,  fusiform,  enlarged  at  the  inferior  third, 
and  tapering  gently  to  the  summit ;  surface  covered  with  regular,  longitudinal  rows  of 
spiny,  projecting  granules,  the  intervening  space  being  finely  shagreened. 

Dimensions. — Height,  one  inch  and  four  tenths ;  transverse  diameter,  one  inch  and 
three  tenths. 

Description. — A  very  good  figure  of  a  fragment  of  the  test  and  spines  of  this  urchin 
was  given  in  Parkinson's  '  Organic  Ren)ains,'^  pi.  iv,  fig.  2,  and  a  fair  drawing  of  the 
upper  surface  of  the  shell  in  pi.  i,  fig.  11  ;  both  were,  unfortunately,  unaccompanied  by 
any  description. 

This  beautiful  species  attains  a  considerable  size ;  the  test  is  circular,  and  nearly 
equally  depressed  at  both  poles  (PI.  VI,  fig  1,  c) ;  the  ambulacral  areas  are  very  narrow 
and  flexuous,  with  six  rows  of  granules  at  the  equator,  diminishing  to  four  rows  at  both 
poles ;  the  external  rows  are  the  largest  and  most  persistent,  and  the  internal  rows  are 
found  only  in  the  wide  portion  of  the  area ;  in  large  shells  there  are  many  smaller  granules, 
dispersed  among  the  regular  rows  (PI.  VT,  fig.  1,  d) ;  the  poriferous  zones  are  very  narrow 
and  depressed,  following  the  flexures  of  the  areas ;  the  pores  are  small,  round,  closely 
approximated,  and  disposed  obliquely,  having  a  minute  granule  on  the  septum,  and  there 
are  twenty-four  to  twenty-six  pores  opposite  one  of  the  larger  plates  (fig.  1,  r/). 

The  inter-ambulacral  areas  are  very  wide,  and  there  are  from  four  to  five  large  plates  in  a 
column  ;  in  consequence  of  the  prominence  of  the  scrobicular  circle,  each  plate  is  thickened 
at  the  middle,  and  the  lines  of  sutures  between  the  plates  are  all  very  much  defined,  in 
consequence  of  the  plate  sloping  away  from  the  scrobicular  circle  to  the  suture  ;  the  areolas 
are  wide  and  circular,  and  surrounded  by  a  thick,  prominent  border  (fig.  1,  d),  encircled  by  a 
series  of  seventeen  granules,  each  raised  on  a  distinct,  shield-like,  mammillated  plate ;  the 
boss  is  not  prominent,  its  summit  is  feebly  crenulated  in  young  shells,  and  smooth  in  old 
ones  (PI.  VI,  fig.  1) ;  the  tubercle  is  moderately  large  and  perforated ;  the  plates  near  the 
peristome  (PL  VI,  fig.  1,  b)  are  disproportionately  small  compared  with  those  of  the 
equator  (fig.  1,  c,  d) ;  and  the  last  plate  of  each  column  in  old  shells  (fig.  1,  a,  e,f)  has 
an  elongated  form,  with  a  rudimentary  tubercle,  and  curious  elongated  furrow,  representing 
an  obsolete  areola.  Mr.  Bone  has  given  most  accurate  drawings  of  this  remarkable  plate 
from  the  fiue  specimen  in  the  British  Museum ;  the  singular  star-like  structure  which 
these  plates  form  on  the  upper  surface  of  the  test,  surrounding  the  large  apical  disc,  forms 
a  remarkable  character  of  this  species,  fig.  1,  a. 

The  miliary  zone  is  narrow,  zig-zag,  depressed  in  the  middle,  and  provided  with  fine,close- 
set,  nearly  equal-sized  granules,  very  much  smaller  than  those  surrounding  the  areolas. 

1  '  Organic  Kemaius,'  vol.  iii,  pi.  iv,  fig.  2, 


56  CIDARIS 

The  apical  disc  is  very  wide  (PI.  VI,  fig.  1,  a) ;  the  ovarial  plates  are  large,  thick, 
irregular  pentagons  (fig.  1,  y),  and  the  ocular  plates  are  heart-shaped;  the  surface  of 
both  series  is  covered  with  a  close-set  granulation ;  the  ovarial  and  ocular  holes  are  very 
conspicuous  in  this  species ;  within  the  ovarials  the  external  circle  of  anal  plates  are  found 
i//  siiu  (fig.  1,  a,ff,  //). 

The  mouth-opening  (PI.  VI,  fig.  1,  b)  is  nearly  circular,  and  smaller  than  the  anal 
opening;  the  jaws  are  strong  and  powerful,  as  seen  in  PI.  VII,  fig.  1,  a,  b. 

The  spines  are  long,  cylindrical,  and  fusiform,  thickest  at  the  lower  third,  and  tapering 
gently  from  thence  to  the  point  (PI.  VI,  figs.  2 — 5) ;  they  are  covered  with  small,  spiny, 
equal-sized  granules,  the  points  of  which  are  directed  outwards  ;  they  are  arranged  in 
regular,  longitudinal  rows,  with  a  valley  between  them  ;  the  prickles  diminish  in  size  near 
the  collar,  and  at  the  summit  of  many  of  the  large  spines  the  rows  of  granules  form  a 
stellate  termination  (PI.  VI,  fig.  3,  a,  b,  c) ;  the  valleys  are  covered  with  a  finely  corriigated 
surface,  the  eminences  forming  microscopic  longitudinal  lines.  The  neck  is  very  short 
and  delicately  striated  (fig.  4,  b),  the  head  moderately  large,  and  the  milled  ring  not 
prominent ;  the  rim  of  the  acetabulum  is  feebly  crenulated,  and  its  concavity  contains 
a  deep  depression  for  the  round  articular  ligament ;  the  length  of  the  large  spines,  figured 
in  PI.  VI,  figs.  3  and  4,  contained  in  the  British  Museum,  is  two  inches  and  nine  tenths. 
One  figured  by  ^I.  Cotteau,  from  the  French  Chalk,  is  three  inches  long. 

Affinities  and  Differences. — Cidaris  sceptrifera  so  closely  resembles,  in  many  points  of 
structure,  Cidaris  subvesiculosa,  d'Orbigny,  that  by  some  they  have  been  thought  to  be 
varieties  of  one  species ;  the  facts  on  which  their  distinctness  may  be  maintained  are  the 
following :  Cidaris  subvesiculosa  has  a  more  elevated  test,  with  a  greater  nimiber  of  plates 
in  a  column,  the  areolas  are  smaller  and  less  depressed,  the  circle  of  scrobicular  granules 
is  less  prominent,  and  the  obsolete  tubercles  on  the  upper  plates  of  the  columns  are 
smaller,  more  numerous,  and  differently  formed  ;  the  grannies  covering  the  miliary  zone 
are  smaller,  and  more  regularly  disposed  in  rows  radiating  from  the  areola.  The  grand 
distinction  is  found  in  the  spines,  which  are  much  smaller  in  C.  sceptrifera,  tapering,  but 
not  fusiform,  and  covered  with  longitudinal  serrated  lines.  Compare  the  different  excellent 
figures  of  Cidaris  subvesiculosa,  d'Orbigny,  in  PL  VIII,  with  the  admirable  drawings  of 
Cidaris  sceptrifera,  Mantell,  in  PI.  VI  and  VII. 

Locality  and  Stratigrapldcal  Position. —  Cidaris  sceptrifera  is  found  in  the  Upper 
"White  Chalk  of  Kent,  Sussex,  and  Wilts.  The  truly  magnificent  specimens  figured  in 
Pi.  VI,  fig.  1,  and  PI.  Vllrtf,  fig.  I,  belong  to  the  British  ]Museum;  the  specimens  figured  in 
PI.  VI,  fig.  2,  and  PI.  VII,  fig.  1,  belong  to  the  Museum  of  the  Royal  School  of  Mines. 
I  need  scarcely  add  they  are  the  finest  known. 

In  France,  M.  Cotteau  enumerates  the  following  localities  in  which  this  species  is 
found :  Dieppe  (Seine- Inferieure) ;   la  Faloisc   (Somme) ;  Vernonnet,   Giverny,   Civieres, 


FROM  THE  WHITE  CHALK.  57 

Petit-Anclelys,  Pinterville  pres  Louviers,  Senneville,  Evreux  (Eure) ;  Notre-Dame-du-Thil 
Frocourt,  les  Blamonts,  Thcrdonne,  Pouilly,  Reims,  Eroyes,  la  Herelle,  le  Mesnil-Saint- 
Finnin,  Mory  (Oise)  ;  Clialons-sur-^Manie  (Manic) ;  la  Fertc-Loupiere  (Yonne) ;  Claclialoze, 
Maintenoii  (Seine-et-Oise) ;  Marion  (Sarthe)  ;  Villedieu,  Limeray  (Loir-et-Cheij ;  le 
Menil-Saiiit-Tliomas  (la  Poterie)  (Eure-et-Loir)  ;  Anbeterre  (Charente) ;  Talmont,  Saint- 
Georges,  Royan  (Charente  Inferieure).  Etage  Senonien.  Saiut-Paterne  (Sarthe)  ;  Etage 
Tiironien,  zone  Terebratella  Bourgeoisii. 

History. — First  figured  by  Parkinson  in  1811;  the  test  and  spines  arc  both  well 
drawn,  so  that  no  doubt  as  to  the  species  intended  can  exist,  although  no  description  of 
the  urchin  was  given.  In  1823,  Mantell  figured  one  of  the  spines,  and  gave  it  the 
name  which  it  still  retains.  This  species  was  not  indicated  in  France  until  1840,  when 
it  was  entered  in  M.  Agassiz'  Catalogus  si/sfemaficus ;  since  then  its  test  and  spines  have 
been  found  in  the  localities  enumerated  above. 


CiDARls  SUBVESICULOSA,  (V  Orhigny.     PI.  VIII,  figs.  2,  4,  5,  G. 

CiDARES  PAPILLAT.E,  Parliinson.     Organic   Remains,   vol.  iii,   p.  39,  pi.  iv,  fig.  3, 

1811. 
CiDARis  CKETOSA,  Mantell.     Geol.  of  Sussex,  Trans.  Geol.  Soc.,vol.  iii,  p.  205, 

18:55. 

—  PAPiLLATA,  Mantell.     Geol.  of  Sussex,  p.  194,  pi.  xvii,  fig.  13,  1822. 

—  CKETOSA,  Morris.     Catal.  of  British  Fossils,  p.  50,  1843. 

—  VESICULOSA,  Morris.     Ibid,,  p.  51,  1843. 

—  PAPILLATA,  Reiiss.     Die  Versteinerungen  der  Bohmischen  Kreideforma- 

tion,  p.  57,  pi.  XX,  fig.  22,  1846. 

—  CRETOSA,  Graves.     Essai  suf  la  Topog.    Geog.    du   Departement   de 

rOise,  p.  688,  1847- 

—  —  Bronn.     Index  Palaeontologicus,  p.  298,  1848. 

—  SUBVESICULOSA,  cfOrhigny.     Prod,  de  Paleontol.  Strat.,  t.  ii,  p.  274,  1850. 

—  OVATA,  Sorignet.     Ours.  Foss.  de  I'Eure,  p.  9,  1850. 

—  AMBIGUA,  Sorignet.     Ibid.,  p.  10,  1850. 

—  VESICULOSA,  Forbes,  in  Dixon's    Geol.  of  Sussex,   p.  338,  pi.  xxv,  figs. 

1—4,  1850. 

—  —  Quenstedt.     Handbuch  der  Petrefactenkuude,    p.    375,  pi. 

xlviii,  fig.  49,  1854. 

—  —  Forbes,  in  Morris's   Catalogue  of  British  Fossils,  2nd  ed., 

p.  75,  1854. 

—  SUBVESICULOSA,     Desor.     Synopsis  des  Echinides  Foss.,  p.  13,  pi.  v,  fig.  27, 

1855. 

—  GRAKULO-STRIATA,  Desor.     Ibid.,  p.  14,  pi.  v,  fig.  26,  1855. 

—  OVATA,  Desor.     Ibid.,  p.  14. 

—  AMBIGUA,  Desor.     Ibid.,  p.  15. 

8 


58  CIDARIS 

CiDABis  SUBVESICDLOSA,  Coqiiatid.     Bull.  Soc.  Ge'ol.  de  France,  2e  serie,  tora.  xvi,  p. 

1013,  1860. 

—  —  Cotteau  et  Triger.     £chin.  du  dep.  de  la  Sarthe,  p.  250,  pi. 

xli,  figs.  1—9,  1860. 

—  —  Cotteau.    PaleoDtologie  Fran9aise,  Ter.  Cretace,  tome  vi,  p. 

257,  Pis.  1059—1061,  1863. 

Test  large,  circular,  inflated,  nearly  equally  depressed  at  both  poles ;  ambulacral  areas 
slightly  flexed,  wide,  with  six  rows  of  nearly  equal-sized  granules  at  the  equator, 
diminishing  to  four  and  two  rows  at  the  poles,  the  external  series  being  the  largest  and 
most  persistent ;  poriferous  zones  narrow,  depressed,  and  composed  of  simple  oval  pores, 
separated  from  each  other  by  an  elevation  of  the  septum  ;  inter-ambulacral  areas  wide,  si,x 
or  seven  large  plates  in  a  column ;  the  three  equatorial  plates  with  large  areolae,  those 
near  the  peristome  small,  and  the  two  upper  plates  near  the  disc  with  small  rudi- 
mentary tubercles ;  areola)  circular,  depressed,  surrounded  by  a  ring  of  mammallated 
granules,  boss  flat,  with  a  smooth  summit,  tubercle  moderate  and  perforated ;  miliary  zone 
wide,  filled  with  fine  close-set  homogeneous  granules,  disposed  in  very  regular  horizontal 
lines,  radiating  from  the  scrobicular  circle  to  the  border  of  the  plates ;  peristome  small 
and  pentagonal ;  apical  disc  large,  ovarial  plates  wide,  narrow,  and  perforated  at  a 
distance  from  the  border ;  ocular  plates  heart-shaped,  with  marginal  orbits.  Two  con- 
secutive series  of  cuboidal  anal  plates  arranged  within  the  pentagonal  area  formed  by  the 
ovarials  ;  vent  small  and  sub-central. 

Spines  slender,  elongated,  and  cylindrical ;  surface  covered  wjth  longitudinal  elevations, 
having  a  fine  serrated  or  spinous  border  gradually  becoming  attenuated  towards  the  base ; 
neck  short,  with  longitudinal  lines ;  milled  ring  prominent,  articular  surface  without 
crenulations. 

Dimensions. — Specimen  fig.  5 — height,  one  inch  and  one  tenth ;  transverse  diameter, 
one  inch  and  seven  tenths. 

Description. — This  urchin  has  been  mistaken  for  Cidaris  vesiculosa,  Goldf.,  from 
which  it  difiers,  however,  in  many  important  characters ;  the.se  have  already  been  indicated 
in  the  description  of  that  species  (p.  41).  The  test  is  in  general  of  moderate  size,  and 
nearly  equally  depressed  at  both  poles ;  the  ambulacral  areas  are  slightly  flexed,  with  six 
rows  of  granules  at  the  equator ;  the  external  rows  have  larger  mammillated  granules  than 
the  inner  rows,  which  gradually  disappear  as  the  area  becomes  narrower  near  the  peristome 
and  disc ;  the  poriferous  zones  are  narrow,  depressed,  and  sub-flexuous ;  the  pores  are 
oval,  and  oblique  as  they  approach  the  disc,  and  the  septa  have  small  elevated  granules 
between  the  holes.  The  inter-ambulacral  areas  are  large,  the  plates  wide  and  deep,  six  or 
seven  in  a  column  (PI.  VIII,  figs.  4,  5),  the  areolas  are  circular  and  moderately  depressed ; 
they  are  widely  spaced  out  at  the  upper  surface,  and  placed  closer  together  at  the  infra- 


FROM  THE  WHITE  CHALK.  59 

marginal  region  and  near  the  peristome  ;  the  margin  is  surrounded  by  a  complete  circle  of 
large  mammillated  granules  raised  on  sliield-like  plates.  On  the  two  uppermost  plates  of 
each  column  the  areolae  are  very  narrow,  or  altogether  obsolete  (fig.  4,  a).  The  boss  has  a 
flat  smooth  summit  (fig.  1,  c),  and  the  large  tubercle  is  deeply  perforated  (fig.  1,  c  and  d). 
The  miliary  zone  is  very  wide  at  the  equator,  and  becomes  narrower  near  the  peristome 
and  the  disc.  It  is  more  or  less  depressed  in  the  middle,  along  the  line  of  the  sutures, 
and  covered  with  fine  homogeneous  granules  set  closely  together;  the  granules  are 
arranged  in  regular  horizontal  lines  (fig.  1,  c,  d,  e),  which  radiate  from  the  circumference 
of  the  areolae  to  the  border  of  the  plate. 

The  apical  disc  is  large  and  pentagonal  (fig.  4,  a,  b),  and  well  preserved  in  situ  in  the 
fine  specimen,  fig.  4,  a.  The  five  large  ovarial  plates  have  an  irregular  rhomboidal  form, 
with  the  ductal  holes  near  the  border ;  the  oculars  are  heart-shaped,  and  have  marginal 
orbits ;  the  anal  plates  form  a  double  series  within  the  discal  circle,  and  the  vent  (fig.  4,  b) 
is  a  small  e.xcentral  aperture  with  a  third  series  of  small  plates  on  its  anterior  part  only. 
All  the  elements  of  the  disc  are  closely  covered  with  the  same  style  of  grannies  that  fill 
the  miliary  zone. 

The  peristome,  smaller  than  the  discal  opening,  is  of  a  pentagonal  form ;  in  none  of 
our  specimens  are  the  dental  pyramids  preserved. 

The  spines  are  long,  slender,  cylindrical,  with  longitudinal  ribs  having  a  spinous 
border  (fig.  2,  a,  b) ;  the  valleys  between  the  elevations  have  a  finely  chagreened  surface ; 
the  neck  is  short  and  striated,  the  head  moderately  large,  and  the  milled  ring  prominent 
(fig.  2,  c).  The  acetabulum  has  a  smooth  rim.  One  spine  must  have  measured  2^  inches 
in  length.  The  large  mammillated  granules  surrounding  the  areolae  supported  small,  fiat, 
triangular  spines  (fig.  6),  having  their  surface  ornamented  with  longitudinal  microscopic 
lines,  and  articulated  to  the  tubercle  by  a  semicircular  depression  at  the  base.  I  have 
figured  one  of  these  scrobicular  spines  at  fig.  6,  where  the  line  shows  the  natural  size,  and 
the  figure  is  enlarged  four  diameters. 

Affinities  and  differences. — This  species  has  long  been  considered  to  be  the  Cidaris 
vesiculosa,  Goldf.,  but  is  distinguished  from  that  urchin  in  having  the  ambulacra  less 
flexed,  a  greater  number  of  plates  in  the  inter-ambulacral  colnmns,  the  upper  tubercles' 
of  both  series  rudimentary,  and  in  having  the  granvdes  in  the  miliary  zone  arranged  in 
horizontal  rows.  Cidaris  vesiculosa,  Goldf.,  has  a  smaller  test,  the  ambulacra  much  more 
flexed,  the  plates  in  a  column  fewer,  the  tubercles  consequently  wider  apart,  the  upper 
tubercles  largely  developed,  and  the  grannies  in  the  miliary  zone  not  arranged  in  hori- 
zontal rows.  The  spines  in  C.  snbvesiculosa  are  long,  slender,  and  tapering ;  those  in  C. 
vesiculosa  are  shorter  and  thicker.  This  urchin  so  closely  resembles  C.  perlafa,  Sorignet, 
and  C.  Vcndocinensis,  Ag.,  that  they  appear  to  me  to  be  only  varieties  of  C.  subvesiculosa, 
d'Orbig. ;  the  spines  of  the  latter  likewise  closely  resemble  those  attributed  to  C.  serrata, 
Desor.     It  is  possible  that  if  a  collection  of  good  type-specimens  of  these  different  reputed 


60  CIDARIS 

species  were  compared  with  each  other,  they  would  be  found  to  be  only  so  many  cognate 
varieties  of  one  forui. 

Locality  and  Stratigraphical  position. — Tliis  species  is  found  in  the  Upper  Chalk  of 
Kent,  Sussex,  and  Wilts. 

In  France  M.  Cotteau  gives  the  following  localities  in  which  it  is  very  common  in  the 
Etages  Turonien  et  Senonien  :  Bolbec  (Seine-Inferieure) ;  Houguemarre,  Vernonnet,  Petit- 
Andelys  (Eure) ;  Notre-Dame-du-Thil,  Tartigny  (Oise) ;  la  Ealoise  (Somme) ;  Saint- 
Eraimbault,  IMar^on,  les  Menus  (Sarthe) ;  Yilledieu,  Villiers  (Loir-et-Cher) ;  Semblancay, 
Limeray  (Indre-et-Loire) ;  Briolay  (Maine-et-Loire) ;  Barbezieux,  Aubeterre,  Lavalette, 
Salles  (Charente) ;  Royan,  Saint-Georges  Talmont,  Saintes,  Cognac  (Charente-Inferieure) ; 
Perigueux,  Tretissac,  Neuvic  (Dordogne) ;  Bugarach,  Soulatge  (Aude). 

History. — This  urchin  was  first  figiu-ed  by  Parkinson  in  1811.  The  test  and  spines  are 
sufficiently  well  drawn,  in  the  absence  of  a  description,  to  enable  us  to  identify  the  species. 
In  1822  Mantell  described,  under  the  name  C.  cretosa,  a  Cidaris  represented  by  Parkin- 
son ('Organic  Remains,'  Vol.  Ill,  PL  I,  fig.  11),  and  united  to  fig.  3,  PI.  IV,  of  the 
same  work,  which  served  as  the  type  of  C.  snhvesicidosa.  Professor  Eorbes  identified  this 
species  with  the  C.  vesiculosa,  Goldf.,  and  figured  it  under  that  name  in  Dixon's  '  Geology 
of  Sussex.'  In  1850  M.  d'Orbigny,  in  his  'Prodrome  de  Paluontologie,'  separated  it  from 
that  form  under  the  name  subvesiculosa,  which  has  been  adopted  by  MM.  Desor,  Cotteau, 
and  other  authors. 


Cidaris  Merceyi,  Cotteau.     PI.  VIII,  figs.  1,  2,  3. 

Cidaris  Merceyi,  Cotteau.     Paleont.  Fran9aise,  Ter.  Cretace  Ecbinoderraes,  toin.  vii, 
p.  281,  pi.  1068,  1862. 

Test  large,  circular,  and  elevated  above,  inflated  and  depressed  below;  ambulacra 
narrow,  depressed,  and  slightly  flexed ;  two  rows  of  small  regular  mammillated  granules 
on  the  external  border,  and  four  rows  of  smaller,  irregular  granules  on  the  central  portion 
of  the  area ;  poriferous  zones  narrow,  flexed,  composed  of  round  pores  in  oblique  pau's ; 
inter-ambulacra  wide,  six  or  seven  large  plates  in  a  column ;  tubercles  well  developed  at 
the  base  and  equator,  but  small  and  obsolete  on  the  upper  surface ;  areolae  circular, 
depressed,  margin  surmounted  by  a  circle  of  regular  mammillated  granules. 

Dimensions. — Height,  two  inches ;  transverse  diameter,  two  and  a  half  inches. 

Description. — This  remarkable  urchin,  which  appears  to  be  an  elevated  variety  of 
Cidaris  subvesiculosa,  has  been  described  by  j\I.  Cotteau  as  a  distinct  species  under  the 


FROM  THE  WHITE  CHALK.  61 

name  C.  Mcrceyi.  The  test  is  large  and  circular,  elevated  at  the  upper  surface,  inflated  at 
the  equator,  and  flat  at  the  base  (fig.  1,  a,  b).  The  arabulacral  areas  are  narrow  and 
slightly  flexed,  much  depressed  at  the  medium  suture,  and  furnished  at  the  widest  part 
with  six  rows  of  granules.  The  two  marginal  rows  have  larger  granules,  very  regular  in 
size  and  arrangement,  and  raised  on  small  plates  (fig.  1,  c) ;  the  four  inner  zones  are 
much  smaller  and  less  regular  (fig.  1,  c) ;  the  poriferous  zones  are  narrow,  deeply  sunk,  and 
slightly  bent ;  the  small  round  pores  are  disposed  in  oblique  pairs,  of  which  there  are 
twenty-one,  opposite  one  large  equatorial  plate  (fig.  1,  c). 

The  inter-ambulacral  areas  are  wide  and  largely  developed ;  there  are  from  six  to 
seven  plates  in  each  column,  of  which  the  four  or  five  lower  plates  have  large  areolae,  with 
moderately  sized  tubercles  ;  the  two  uppermost  plates  are  destitute  of  areolae,  and  have 
small  rudimentary  tubercles  (fig.  1,  a  and  b).  The  areolae  at  the  base  and  equator  are 
narrow  and  deeply  depressed,  well  spaced  out  from  each  other  at  the  equator,  and  set 
closer  together  at  the  base.  The  scrobicular  margin  of  one  of  the  equatorial  plates  is 
surrounded  by  a  circle  of  eighteen  regular  mammillated  granules,  larger  than  those  filling 
the  miliary  zone  (fig.  1,  c) ;  the  boss  is  prominent,  the  summit  smooth,  and  the  tubercle 
moderately  large  and  widely  perforated  (fig.  1,  d).  Above  the  equator  the  two  or  three 
upper  tubercles  entirely  change  their  character,  the  areolae  become  extremely  narrow  or 
disappear  (fig.  1,  b),  and  the  tubercle  becomes  a  mere  rudiment  in  the  midst  of  the  miliai-y 
granulation.  The  plate  of  this  series  nearest  the  equator,  the  third  from  the  discal  end, 
supports  a  very  narrow  areola  (fig.  1,  e)  with  a  small  tubercle,  and  on  the  two  uppermost 
plates  the  tubercles  are  mere  warty  rudiments  suiTounded  by  granules. 

The  inter-ambulacral  plates  are  large,  convex,  and  inflated  (fig.  \,  c,  d,  e)  towards  the 
middle,  and  slope  gently  towards  the  sutures,  which  are  very  well  marked  in  this  species. 

The  miliary  zone  is  wide  and  well  developed,  depressed  in  the  middle  and  between 
the  plates;  the  granules  are  fine,  abundant,  and  homogeneous,  and  arranged  in  regular 
lines  that  radiate  horizontally  from  the  areolae  to  the  borders  of  the  plate  (fig.  1,  c,  d,  e), 
resembling  in  this  respect  C.  subvesiculosa. 

The  mouth-opening  is  small,  and  the  peristome  pentagonal ;  the  upper  surface  of  the 
test  is  fractured,  and  the  disc  absent.  M.  Cotteau,  who  has  figured  a  very  complete 
specimen  of  this  Cidaris,  says  that  the  periproct  is  pentagonal  and  star-shaped,  and  the  disc 
solid  and  inflated,  and  larger  than  the  peristome ;  the  ovarial  plates  are  thick  and  angular, 
their  internal  surface  smooth  and  marked  by  three  facettes  for  articulation  with  the 
external  row  of  anal  plates ;  the  ocular  plates  are  small,  subpentagonal,  deeper  than  wide, 
and  not  notched  at  the  summit  of  the  ambulacra. 

The  spines  have  not  been  found  in  relation  with  the  test. 

Affinities  and  differences. — This  species  resembles  in  so  many  important  particulars 
the  preceding  species,  that  I  hitherto  considered  it  to  be  a  conoidal  variety  of  that  form. 
M.  Cotteau  says  this  is  one  of  the  most  curious  species  of  Cidaris.     Its  form  is  in 


62  CIDARIS 

general  inflated  and  sab-conical,  its  superior  inter- ambulacral  plates  are  entirely  deprived 
of  tubercles,  the  structure  of  its  periproct  and  apical  disc  impart  a  peculiar  physiognomy 
to  it,  and  clearly  distinguish  it  from  its  congeners.  It  is  distinguished  from  C.  sub- 
vesiculosa  by  its  greater  size,  its  inflated  sub-conoidal  form,  its  straighter  ambulacra,  and 
smaller  and  less  regular  granules.  Its  inter-ambulacral  plates  are  more  numerous,  and 
the  three  uppermost  plates  in  each  column  are  entirely  deprived  of  tubercles  in  the 
specimen  figured  by  M.  Cotteau,  and  they  are  small  and  rudimentary  in  the  urchin  figured 
in  our  PI.  VIII,  fig.  2. 

Locality  and  StratiyrapMcal  position. — Collected  from  the  White  Chalk,  where  it  is 
very  rare.  The  fine  specimen  figured  by  Mr.  Bone  belongs  to  Dr.  Bowerbaiik's  collection. 
That  figured  by  ]M.  Humbert  for  M.  Cotteau  was  collected  at  La  Faloise  pres  Breteuil 
(Somme) ;  in  the  Etage  Senouien,  where  it  is  very  rare.  It  belongs  to  M.  Tombeck's 
collection. 


CiDARis  PERORXATA,  Forbes,  1850.     PI.  VII  a,  fig.  2. 


CiDAEis  PERORNATA,       Forbes,  in  Dixon's  Geol.  of  Sussex,  p.  339,  pi.  sxv,  fig.  8. 

1850. 

—  LOXGISPINOSA,  Sorignet.     Ours.  Foss.  de  I'Eure,  p.  19,  1850. 

—  Sarthacensis,  rf'Or%wy.     Prod,  de  Tal.  Strat,  t.  ii,  p.  274,  1850. 

—  perornata,       Forhps,  in  Morris's  Catal.    of  Brit.  Fos.sils,  2nd  edit.,  p.  74, 

li^54. 

—  —  Cotteau.     Paleontologie    Frangaise,  t.    vii,   p.    274,  pi.    1065, 

figs.  3—14,  1862. 

Test  elevated,  melon-shaped.  Ambulacra  nearly  straight,  narrow,  depressed.  Six 
rows  of  small  granules,  the  marginal  the  largest  and  most  regular,  the  inner  small,  with 
intermediate  smaller  ones.  Inter-ambulacra  wide,  seven  or  eight  large  plates  in  each 
column ;  areolai  wide,  circular,  with  a  marginal  circle  of  very  small  granules ;  boss  smooth 
or  slightly  crenulated ;  tubei'cles  small  and  perforate ;  sutures  well  marked,  depressed. 
Spines  long,  cylindrical,  several-ridged ;  ridges  irregular  towards  the  base,  and  serrated, 
the  interstices  granulated. 

Dimensions. — Height,  one  inch  and  eight  tenths ;  transverse  diameter,  two  inches. 


Description. — The  test  of  this  fine  urchin  is  high  and  melon-shaped,  and  reminds  me 
of  C.  mawimus,  from  the  Coral-rag  of   Germany.      The   ambulacral   areas   are  narrow, 


FROM  THE  WHITE  CHALK.  63 

nearly  straight,  and  provided  with  six  rows  of  small  granules ;  the  marginal  series  are  the 
largest,  the  inner  ones  are  small,  and  between  them  are  some  still  smaller  granulets 
scattered  about  the  area.  The  poriferous  zones  are  only  gently  waved,  the  holes  round, 
and  placed  transversely;  there  are  fifteen  pairs  opposite  each  of  the  equatorial  plates. 
The  inter-ambulacral  areas  are  very  regularly  formed ;  the  plates,  about  eight  in  each 
column,  are  large  and  uniform ;  the  areolae  are  wide  and  circular,  and  occupy  the  entire 
depth  of  the  plate;  the  margin  is  surrounded  by  a  circle  of  very  small  mammillated 
granules,  about  twenty-one  in  number,  and  well  spaced  out  from  each  other ;  the  boss  is 
not  prominent,  and  only  some  of  the  summits  are  feebly  crenulated,  whilst  the  others  are 
smooth.  The  tubercle  is  small,  and  deeply  perforated  (fig.  2,  a,  b).  The  miliary  zone  is 
wide,  and  depressed  in  the  middle ;  the  granules  are  fine,  homogeneous,  and  nearly  equal- 
sized,  and  arranged  in  regular  horizontal  rows,  which  follow  the  angles  of  the  median 
sutures.  As  the  areolae  occupy  the  centre  of  the  plates,  there  is  a  considerable  granular 
space  between  the  ambulacral  side  of  the  areolae  and  the  poriferous  zones.  The  sutures 
are  all  very  distinctly  marked,  and  the  median  inter-ambulacral  is  much  depressed.  The 
peristome  is  sub-pentagonal  and  large.  The  spines  are  long,  cylindrical,  and  sub-acumi- 
nated at  the  summit  (fig.  4,  a).  The  stems  are  provided  with  long,  narrow  spines,  projecting 
at.  intervals  from  many  regular,  longitudinal  ridges,  and  having  the  interstices  finely 
granulated  (fig.  4,  c).  For  the  most  part  these  spines  are  equally  and  uniformly  disposed; 
sometimes,  however,  they  lose  their  homogeneity,  and  vary  in  their  height  and  in  pre- 
serving a  longitudinal  disposition.  The  valleys  between  the  ridges  on  the  stem  are 
throughout  covered  with  fine,  delicate,  microscopic,  sub-granular,  longitudinal  striae,  which 
are  only  visible  by  the  aid  of  a  lens  (fig.  4,  c).  The  neck  is  without  ridges  and  spines; 
the  collar  is  long  and  finely  striated,  and  separated  from  the  stem  by  a  distinct  line  (fig, 
4,  b).  The  head  is  large,  the  milled  ring  prominent,  with  thicker  striae  than  those  on  the 
collar,  and  the  rim  of  the  acetabulum  is  smooth  (fig.  4,  ^).    . 

JJJinifies  and  differences. — The  melon-shaped  test,  very  regular  inter-ambulacral  areas, 
areolae  and  tubercles  gradually  increasing  from  the  base  to  the  upper  surface,  added  to  the 
long,  slender  spines,  with  prickly  ridges,  serve  to  distinguish  this  species  from  its  congeners 
of  the  "White  Chalk.  The  spines  resemble  those  attributed  to  C  spinigera,  Cott.,  of  the 
Neocomian  stage,  from  the  middle  of  France,  but  they  manifest  differences  which  are 
sufficiently  distinctive  of  each.  In  C.  perornata  the  spines  arise  from  ridges  at  regular 
intervals,  which  are  absent  in  C.  spinigera. 

Locality  and  Stratigrapldcal  'position. — This  species  was  collected  from  the  White 
Chalk  of  Kent  and  Sussex.  The  specimens  figured  are  from  the  cabinets  of  Dr.  Bower- 
bank  and  Rev.  T.  Wiltshire. 

The  foreign  localities  of  this  urchin  are,  according  to  M.  Cotteau,  Vernonnet, 
Giverney,  Pinterville,  ITouguemarre  (Eure),  Epagny  (Somme),  Tartigny  (Oise),  La  Fleche, 
(Sarthe);  where  the  spines  are  common  in  the  Etage  Senonien. 


64  CIDARIS   FROM   THE  WHITE   CHALK. 

msfo>y.—T\\e  late  Frederick  Dixon,  Esq.,  F.G.S.,  and  Professor  Forbes,  first  figured, 
in  1850,  the  test  and  spines  of  this  species  from  tlie  White  Chalk  of  Sussex,  and  the  latter 
described  it  as  a  new  species  under  the  name  C.  perornata.  M.  I'Abbc  Sorignet  described 
the  spines  which  he  collected  in  the  department  of  the  Eure  imder  the  name  C.  loiif/ispiiwsa, 
and  Professor  d'Orbigpy  those  found  in  the  Sarthe  as  C.  Sarf/iacensis.  As  Professor 
Forbes  first  figured  and  described  the  urchin,  and  the  other  authors  only  described  it,  the 
name  of  the  figured  specimen  is  for  this  reason  retained. 


CiDAiiis  HiRTJDO,  Soriffnet,  1850.     PI.  X,  figs.  1 — 5  ;  PI.  IX. 

CiDARis  HiRUDO,  Soriffnet.     Ours.  Foss.  de  I'Eure,  p.  17,  1850. 

—  SCEPTUIFEEA,  Forbes,  in  Dixon's  Geol.  of  Sussex,  p.  338,  pi.  xxv,  figs.  32  and  33, 

—  —  var.  spiNis  TRUNCATis.     1850. 

—  SULCATA,         Forbes,  in  Morris's  Catal.  of  Brit.  Fossils,  2nd  edit.,  p.  75,  183-1. 

—  —  Woodward.    Mem.  of  Geol.  Surv.,  Decade  v,  explanation  of  pi.  v, 

p.  3,  1856. 
•  —        HIRUDO,  Cotteau.     Paleontologie  Fran9aise,  torn,  vii,  p.  2-1-4,   pi.    1054, 

figs.  6 — 16. 

• 

Test,  in  general,  of  moderate  size,  sometimes  large,  slightly  depressed  equally  at  both 
poles ;  ambulacial  areas  narrow,  flexed,  with  six  rows  of  granules  at  the  equator,  dimin- 
ishing to  two  at  the  apertures  ;  in  the  two  external  rows  the  granules  are  larger  and  mara- 
millated,  in  the  inner  rows  they  are  very  regularly  disposed,  but  smaller  and  unequal; 
poriferous  zones  very  narrow,  depressed,  and  flexed,  and  formed  of  small  round  pores, 
the  intervening  septum  having  a  slight  divisional  elevation ;  inter-ambulacral  areas  wide ; 
columns  with  five  or  si.K  large  plates;  areola  moderate,  depressed,  margin  elevated,  and 
surroimded  by  a  circle  of  mammillated  granules,  well  spaced  out  apart ;  boss  with  a 
smooth  summit ;  tubercle  moderate  in  size  and  perforated,  the  areolae  and  tubercles  in- 
creasing gradually  in  magnitude  from  the  peristome  to  the  upper  part  of  the  colimuis ; 
miliary  zone  depressed  in  the  middle,  and  filled  with  equal-sized  granides ;  line  of  the 
sutures  well  marked  thronghout. 

Spines  elongated,  cylindrical,  subfnsiform  ;  stem  enlarged  at  the  middle,  and  tapering 
at  the  upper  third,  summit  truncated  and  presenting  a  stellate  figure  ;  the  longitudinal 
ridges  on  the  stem  have  a  granuliform  structure,  and  the  intervening  valleys  are  finely 
chagreened  ;  the  neck  is  short,  distinctly  defined,  and  marked  with  longitudinal  microscopic 
lines ;  the  head  is  small,  the  milled  ring  prominent,  and  the  acetabulum  has  a  smooth  ring 
around  the  brim. 

i)M«e;Mvo«s.— Specimen  PI.  X,  fig.  2 — height,  nine  tenths  of  an  inch  ;  transverse 
diameter,  one  inch  and  four  tenths.  Specimen  PI.  IX — height,  one  inch,  and  three 
tenths;  transverse  diameter,  one  inch  and  nine  tenths  (?). 


THE 


PALiEONTOGRAPHICAL  SOCIETY, 


INSTITUTED  MDCCCXLVII. 


VOLUME  FOE  1867. 


LONDON 


MOCCCLXVIII. 


A    MONOGRAPH 


ON    THE 


BRITISH     FOSSIL 


ECHINODERMATA 


FROM 


THE  CRETACEOUS  FORMATIONS. 


BY 


THOMAS  WRIOHT,  M.D.,  F.R.S.  Edin.,  F.O.S., 

CORRESPONDING    MEMBER  OF   THE    BOYAL   SOCIETY   OF  SCIENCES  OF   LIEGE,    THE    SOCIETY  OF 

NATUEAX  SCIENCES   OF  NEUFCIIATEL,   AND    SENIOR   SURGEON   TO 

THE    CHELTENHAM    HOSPITAL. 


VOLUME    FIRST. 

PART  SECOND. 
ON   THE   CIDARIDtE   AND  BIADEMAD.E. 

Pages  65-113;  Plates  IX,  X,  XII— XXL,  XXI  a,  XXI  b. 

LONDON: 

PRINTED   FOR  THE   PAL/EONTOGRAPHICAL    SOCIETY. 

1868. 


PRINTED    EY   J.    E.    ADLAKD,    BARTHOLOMEW    CLOSE,    E.C. 


CIDARIS  FROM  THE  WHITE  CHALK.  65 

Description. — This  beautiful  Cidaris,  formerly  identified  by  Professor  E.  Forbes  as  a 
variety  of  C.  sceptri/era,  and  afterwards  catalogued  by  him  as  a  distinct  species,  under  the 
name  C.  sulcata,  had  been  previously  considered  by  the  Abbe  Sorignet,  from  its  spines 
alone,  as  a  new  form,  and  described  in  1850  as  C.  hirudo  in  his  work  on  the  '  Oursins 
fossiles  du  departement  de  I'Eure,'  and  this  name  has  the  priority. 

The  test  of  the  fine  specimen  belonging  to  Henry  Willett,  Esq.,  F.G.S.,  and 
fully  illustrated  in  PI.  IX.,  fig.  1  a,  h,  c,  attains  a  moderate  size,  is  inflated  at  the 
equator,  and  equally  flattened  at  the  poles.  The  ambulacral  areas  are  narrow,  sinuous, 
and  band-like,  forming  prominent,  wefl-marked  segments  in  the  test,  filled  with  small, 
close-set,  regularly  arranged  rows  of  granules ;  there  are  six  rows  at  the  equator, 
four  rows  in  the  upper  and  lower  thirds,  and  two  rows  only  near  the  discal  and 
oral  apertures.  The  most  prominent  granules  are  in  the  external  rows;  they  are 
slightly  mammillated  and  extend  throughout  the  entire  area.  PI.  IX,  fig.  3  b,  is  an  equa- 
torial inter-ambulacral  plate,  with  the  ambulacral  area  attached,  magnified  three  diameters. 
In  the  second  row  the  granules  are  nearly  as  large,  and  extend  through  eight  tenths  of  the 
area ;  the  third  rows  extend  through  the  height  of  two  large  plates ;  the  granules  are 
set  very  closely  together,  and  regularly  arranged  in  transverse  rows.  The  poriferous  zones 
are  narrow,  depressed  and  flexuous,  fig.  2  (5 ;  the  pores  are  small  and  round,  and  the  septum 
supports  a  small  round  granule ;  the  entire  series  of  septal  granules  forms  a  moniliform 
line  between  the  pores,  which  gives  an  apparent  lateral  extension  to  the  width  of  the  area ; 
and  opposite  one  of  the  large  plates  there  are  twenty-three  pairs  of  pores. 

The  inter-ambulacral  areas  are  wide,  the  plates  composing  them  being  deep  and  broad, 
five  or  six  in  each  column ;  the  areolas  are  circular  and  moderately  depressed ;  they  are 
closely  approximated  on  the  under  side,  wider  apart  at  the  equator,  and  still  further  apart 
above. 

PI.  IX,  figs.  1  and  3,  PI.  X,  figs.  1,3,  3,  show  the  character  of  t'he  areolae ;  the  margin 
is  slightly  elevated  (PI.  IX,  fig.  3  H)  and  encircled  by  a  row  of  larger  mammillated 
granules ;  the  uppermost  plate  in  each  alternate  column  has  a  rudimentary  wart-like 
tubercle  without  areola  (PI.  IX,  fig.  1  a,  h) ;  and  in  the  other  column  the  tubercle  is  small, 
but  complete,  and  surrounded  by  a  narrow  shallow  areola  (fig.  \  a,  b) ;  the  base  has  a 
smooth  flat  summit,  with  only  rare  indications  of  crenulations ;  those  in  fig.  3  b,  are 
strongly  drawn  :  the  tubercle  is  large  and  perforated.  The  miliary  zone  is  wide,  depressed 
along  the  middle  of  the  area,  and  along  the  transverse  lines  of  the  sutures  :  the  granula- 
tions on  the  surface  of  the  plates  arc  large  in  size  and  uniform  in  arrangement  thereon. 

The  apical  disc  (PI.  IX,  fig.  3  a)  is  large,  and  composed  of  five  ovarial  and  five 
ocular  plates ;  the  rhomboidal  ovarials  are  widely  perforated,  and  the  cordate  ocidars  have 
small  marginal  orbits  in  the  disc  (fig.  3  c)  ;  the  aperture  is  pentagonal,  and  there  are  in- 
dications of  the  outer  series  of  small  anal  plates. 

The  mouth-opening  (PI.  IX,  fig.  3,  and  PI.  X,  figs.  1  a,  and  3  b)  is  small,  and  the 
peristome  slightly  pentagonal ;  in  PI.  IX,  fig.  3,  there  is  a  rudiment  of  a  jaw  and  tooth. 


66  CIDARIS 

The  spines  exhibit  a  considerable  variation  of  form ;  in  some  they  are  elongated  and 
cylindrical,  as  in  PI.  IX,  fig.  1  ^ ;  or  elongated  and  subfusiform,  as  in  fig.  5,  and  PI.  X, 
fig.  1  h,  and  figs.  .5,  6.  In  all  the  stem  is  slightly  enlarged  in  the  middle,  and  tapers 
towards  the  upper  third.  The  surface  in  some  specimens  is  sculptured  with  fine  longi- 
tudinal lines,  as  in  PI.  IX,  fig.  1,  and  Pi.  X,  figs.  1,  4,  6;  or  has  granulated  ridges  with 
intervening  valleys,  as  in  PI.  IX,  fig.  5,  and  PI.  X,  fig.  5.  The  summit  is  truncated  more 
or  less  in  all  the  specimens,  and  exhibits  a  stellate  figure  with  several  central  convexities  as 
in  PI.  IX,  figs.  4  a,  and  4  c,  5,  the  radii  being  formed  by  the  development  of  the  longi- 
tudinal ridges. 

In  the  more  finely  sculptured  spines  the  longitudinal  lines  on  the  stem  have  a  granuliform 
structure;  the  intervening  valleys  are  finely  shagreened  throughout,  and  provided  with 
delicate  subgranular  striae.  The  neck  is  short,  distinctly  defined,  with  a  finely  sculptured 
line  above  the  ring  (PI.  IX,  figs.  4,  5,  PI.  X,  figs.  1,  4,  6). 

The  milled  ring  is  moderately  prominent,  with  coarser  lines  than  those  on  the  neck ;  the 
articular  cavity  is  smooth,  or  has  some  feeble  crcnulations  on  its  margin  (PI.  IX,  figs.  4, 
5,  PI.  X,  figs.  1,  4,  6). 

Affinities  and  Differences. — This  form  has  long  been  considered  to  be  a  mere  variety  of 
C.  sceptrifera ;  the  proximal  discal  plate,  liowever,  has  generally  a  rudimentary  tubercle 
of  larger  size  and  rounder  shape  than  that  found  on  C.  sceptrifera.  The  second  discal 
plate  (counting  downv^'ards)  has  the  upper  three  quarters  of  the  boss  much  more  strongly 
crenulated  than  in  the  other  species  (at  p.  G4  the  upper  bosses  of  C.  hirudo  were 
accidentally  stated  to  be  not  crenulated).  The  large  size  of  the  areolas,  their  comparative 
continuity,  the  prominent  raammillated  granules  upon  their  circumference,  and  the 
circumstance  of  the  highest  areola  bearing  a  perfect  tubercle  being  distant  from  the  anal 
margin  by  not  more  than  half  its  diameter,  easily  separate  this  species  from  C.  sceptrifera, 
in  which  the  areolas  have  more  sloping  borders,  smaller  and  more  numerous  mam- 
millatcd  granules,  and  in  which  the  highest  areola  bearing  a  perfect  tubercle  is  generally 
distant  from  the  anal  margin  by  the  length  of  its  diameter.  The  spines  are  much 
shorter  and  more  uniform  in  diameter  than  in  C.  sceptrifera,  having  their  greatest 
swelling  midway  between  the  acetabulum  and  summit,  instead  of  towards  the  former ; 
their  extremities  are  more  truncated,  often  becoming  stellate,  as  on  Plate  IX.  fig. 
4  c;  their  surface  is  covered  with  longitudinal  ridges,  armed  with  very  much  shorter 
piny  projections,  often  almost  obliterated ;  the  collar  is  shorter,  and  the  acetabulum  is 
marked  with  stronger  crcnulations.  C.  hirudo  is  a  rather  small  species,  less  than 
C.  sceptrifera,  and  not  so  common.  An  average  size  wiU  be  about  one  inch  and  one 
tenth  in  transverse  diameter,  height  six  tenths,  length  of  spine  one  inch,  greatest 
diameter  of  spine  three  twentieths. 

Locality  and  Strafir/raphical  Position. — The  specimens  I  have  examined  have  been 
collected  from  the  White  Chalk  of  Sussex  and  Gravesend.  In  France  M.  Cotteau 
gives  the  following  localities  where  this  Urchin  is  common — the  Etage  Cenomauien,  de  Havre 


s 


FROM   THE   WHITE   CHALK.  67 

(Seine-Inferieure),  Fourneaiix  la  Madeleine  (Eure),  Saint-Parres  pres  Troyes  (Aube),  Eltage 
Senonien  Inferieure,  Etretat  (Seine  Inferieure),  Tartigny  (Oise),  Chalons-sur-Marne 
(Marae). 

History. — The  Abbe  Sorignet  in  1850  described  a  spine  of  this  species  under  the 
name  C.  hirudo.  The  same  year  the  test  was  well  figured  with  its  spines  attached 
by  the  late  Mr.  F.  Dixon,  and  described  by  the  late  Professor  Forbes  as  C.  sceptrifera 
var.  spinis  trtmcatis ;  subsequently  it  was  found  that  Mr.  Dixon  had  given  it  the  MS. 
name  C.  sulcata,  under  which  name  it  appeared  in  the  second  edition  of  the  '  Catalogue  of 
British  Fossils/  and  in  Dr.  Woodward's  notes  on  Cidaris  in  the  Fifth  Decade  of  the 
'Memoirs  of  the  Geological  Survey.'  The  Abbe  Sorignet's  name  has  been  properly 
retained  by  M.  Cotteau  in  his  continuation  of  D'Orbigny's  Paleontologie  Fran^aise. 

Cidaris  Dixoni,  Cotteau.     PI.  XI,  fig.  4 ;  PI.  XII,  fig.  6. 

CiDAKis.     Bixon,  Geol.  of  Sussex,  p.  339,  pi.  xxiv,  fig.  25,  1850. 

CiDABis  Dixoni,  Cotteau.  Paleontologie  Fran9aise,  torn,  vii,  p.  238,  pi.  1051,  fig.  78,  1862. 

The  test  of  this  fine  Urchin  is  unknown. 

Description. — Spine  very  large ;  stem  thick,  oblong,  glandiform,  much  enlarged  in  the 
middle,  and  tapering  towards  the  neck  and  apex ;  the  lower  part  is  covered  with  convex, 
scale-like  plates,  arranged  without  much  regularity ;  in  the  middle  part  they  are  larger, 
and  have  much  the  same  character ;  at  the  upper  third  they  are  less  closely  set  together, 
become  ridged,  and  form  granulated  lines,  which  pass  towards  the  summit ;  the  intervening 
valleys  are  covered  with  fine  longitudinal  lines. 

The  neck  is  short  and  smooth,  altliough  there  are  traces  of  longitudinal  lines ;  the 
milled  ring  is  not  prominent,  and  the  articular  cavity  indicates  a  small  tubercle ;  the  rim 
of  the  acetabulum  is  smooth. 

Dimensions. — Length  of  the  entire  spine,  from  acetabulum  to  apex,  l^ths  of  an  inch ; 
length  of  neck  and  head  ^^ths  of  an  inch;  length  of  stem  Ijiths  of  an  inch;  thickness  of 
stem,  at  widest  part,  ^ths  of  an  inch. 

Locality  and  Stratiyraphical  Position. — Found  in  the  Grey  Chalk  near  Folkestone 
by  the  Rev.  T.  Wiltshire,  F.G.S.,  whose  cabinet  contains  a  very  fine  specimen.  Mr. 
Dixon's  type,  which  formed  the  subject  of  fig.  4,  PI.  XI,  is  in  the  collection  of  Henry 
Willett,  Esq.,  F.G.S.  M.  Cotteau  records  two  specimens  from  the  Etagc  Cenomanien, 
at  Havre  (Seine  Inferieure),  where  it  is  very  rare. 

Cidaris  pxeracantha,  Agassiz.     PI.  XI,  fig.  5 ;  PI.  XII,  fig.  5. 

CiDAKIs  PLERACANTHA,  Jyassi:.     Catal.  Syst.  Ectyp.  Foss.,  p.  10,  1840. 
—  —  Sorignet.     Oitrsiiis  foss.  dc  I'Eure,  p.  !,  18.")0. 


68  CIDARIS 

CiDABis  PLEEACAKTHA,  IfOrhigny.    Prodrome  de  Pal.  Strat.,  t.  ii,  p.  2/4,  ^Et.  22,  1850. 

—  —  Dixon.     Geology  of  Sussex,  tab.  xxiv,  fig.  23,  1850. 

—  —  Besor.      Synopsis    des    Echinides     foss.,    t.    vi,   fig.    7 — 10, 

p.  14,  1855. 

—  —  Woodward.       Mem.    Geol.    Siirv.    Decade  V,    Expl.,    pi.    v, 

p.  3,  1856. 

—  —  Cotteau.    Paleontologie  Franc.,  Ter.  Cret.,  torn,  vii,   tab.  1075, 

fig.  1  —  13,  p.  310,  1865. 

Test  unknown. 

Bescrijjtioii. — Spine  very  large,  inflated,  pyriforra,  with  an  obtuse  and  unequally 
rounded  summit ;  stem  ornamented  with  longitudinal  striae,  very  fine  or  subgranular,  and 
visible  near  the  lower  part,  the  upper  part  is  smooth ;  the  stem  suddenly  contracts  to  form 
a  very  short  neck  and  a  small  head  ;  milled  ring  a  little  elevated  and  marked  by  fine  lines  ; 
acetabulum  small  with  a  smooth  ring. 

Spines  of  this  species  are  very  rare  indeed  in  the  English  Cretaceous  rocks.  The 
specimens  collected  at  Meudon,  near  Paris,  and  at  Civieres  (Eure),  vary  much  in  form 
and  dimensions;  some  are  short,  thick,  or  pyriform,  and  have  the  stem  round  or  depressed 
at  the  summit,  or  inflated,  subcylindrical,  accuminated,  or  truncated ;  and  in  a  large 
specimen  before  me  from  France  the  stem  is  bifiu'cated. 

Locality  and  Stratigraplucal  Position. — Mr.  Di.xon's  specimens  were  said  to  have  been 
found  in  the  Grey  Chalk  of  Sussex.  It  occurs  also  in  the  Lower  Chalk  of  Dorking.  The 
specimen  figured,  Plate  XII,  fig.  5,  in  the  Cabinet  of  J.  R.  Capron,  Esq.,  F.G.S.,  came 
from  that  locality. 


CiDARis  Earringdonensis,   Wright.     PI.  II,  figs.  6,  7,  and  8  a,  b,  c. 

Test  known  only  by  isolated  plates. 

Description. — Spines  long,  slender ;  lower  portion  of  the  stem  smooth,  upper  portion 
ornamented  with  longitudinal  rows  of  granules  forming  tuberculated  lines  or  ridges  in 
different  spines,  and  terminating  in  a  star-shaped  summit  at  the  apex.  The  proportional 
length  of  the  smooth  to  the  granulated  ornamentation  of  the  stem  varies  in  different  spines 
— in  some  w^ith  a  long  smooth  portion  the  line  of  separation  is  defined  by  an  annular 
elevation,  in  others  with  a  shorter  smooth  portion  the  granulations  arise  without  any  such 
ridge.  The  valleys  between  the  longitudinal  ridges  have  a  finely  shagreened  surface  ;  the 
head  is  moderate  in  size,  the  milled  ring  prominent,  and  the  small  acetabulum  has  a 
well-defined  marginal  rim. 

The  isolated  plates  of  the  test  are  much  worn  by  friction ;  the  primary  tubercle  is 
small,  the  areola  wide  and  smooth,  and  the  margin  surrounded  by  a  circle  of  large  well- 
defined  granules,  resembling  the  plates  of  Cidaris  vesiculosa. 

Affinities  and  Differences. — The  spines  of  Cidaris  Farringdonensis  differ  so  much  from 


FROM   THE   GREY   CHALK  AND   FARRINGDON   BEDS.  69 

all  other  forms  at  present  known  that  they  cannot  be  mistaken  for  any  other  species,  the 
long  smooth  lower  portion  of  the  stem  forming  such  a  conspicuous  specific  character  of 
this  spine. 

StratiprqjJiiccd  Position. — The  specimens  I  have  figured  were  collected  from  the 
Sponge-gravel  near  Farringdon,  in  Berkshire,  associated  with  Pscudodiadema  rotulare,  Ag., 
Hyposalenia  Wri(/htii,  Desor,  Hyposalenia  Lardyi,  Desor,  Salenia  areolata,  Wahlb.,  and 
two  new  species  of  Echinobrissus,  together  with  the  Amorphozoa  and  MoUusca  that 
characterise  this  remarkable  formation. 

My  kind  friend  the  Rev.  T.  Wiltshire,  F.G.S.,  at  my  request,  has  contributed  the 
following  additional  notes  on  some  rare  tests  and  spines  of  Cidares  in  his  collection. 
These  are  figured  in  Pis.  XH  and  XHI. 

"  In  the  course  of  last  year  you  expressed  the  desire  that  I  should  send  you  some 
notes  in  reference  to  the  fossils  figured  in  Plates  XH  and  XHI  of  your  Monograph  on 
the  Cretaceous  Echinodermata.  In  compliance,  therefore,  with  your  wish,  the  following 
remarks  are  forwarded,  to  be  used  or  rejected  as  may  seem  most  fitting. 

"  The  Urchin  drawn  in  figure  1 ,  Plate  XII,  is  probably  a  new  species  intermediate 
between  Cidaris  sceptrifera  and  C.  subvesiculosa.  I  would  suggest  it  should  be  named 
C.  intermedia ;  it  may  be  thus  defined : — 

Cidaris  intermedia,  Wiltshire.     PI.  XII,  figs.  \  a,\b. 

"Test  moderately  large,  inflated;  ambulacral  areas  narrow,  depressed,  flexuous,  with 
six  rows  of  granules  in  the  middle,  the  outer  two  the  largest,  diminishing  to  four  rows 
above  and  below ;  poriferous  zones  winding,  narrow,  depressed,  at  the  ambitus  about  the 
same  width  as  the  semi-ambulacral  areas,  narrower  above,  wider  below ;  interambulacral 
areas  wide,  plates  large,  five  in  a  column ;  areolas  proximate,  deep,  suboval,  with  an 
elevated  slightly  overhanging  scrobicular  margin,  encircled  by  a  series  of  small  granules, 
equal  in  dimensions  to  those  of  the  outer  row  of  the  ambulacral  areas,  bosses  not  prominent, 
summit  smooth,  tubercle  moderate  in  size,  perforated;  proximal  discal  plate  in  each 
column  with  a  rudimentary  tubercle,  in  a  circular  area ;  miliary  zone  narrow,  filled  with 
small  equal-sized  granules  depressed  along  the  line  of  sutures ;  apical  disc  wide,  of  the  same 
diameter  as  the  peristome ;  ovarial  plates  thick ;  jaws  stout,  triangular ;  spines  long,  slender, 
cylindrical,  slightly  tapering,  surface  marked  by  regular  longitudinal  rows  of  spiny 
projecting  granules,  the  intervening  space  finely  shagreened. 

"  Dimensions. — Height  /^ths  of  an  inch  (the  specimen  being  very  slightly  crushed) ; 
transverse  diameter  1  inch  and  /„ths. 

"  Description. — The  test  of  this  Urchin  is  circular,  and  is  equally  depressed  at  both 


70  CIDARIS 

poles ;  the  ambulacra!  areas  are  narrow  and  flexuous,  rather  more  so  than  in  C.  sceptrifera, 
rather  less  so  than  in  C.  subvesicidosa ;  granules  six  in  number  at  the  ambitus,  diminishing 
to  four  at  the  poles  ;  the  central  rows  at  the  upper  and  under  surfaces  minute  and  irregular ; 
the  four  central  rows  at  the  ambitus  composed  of  granules  of  less  size  than  those  of  the 
exterior  rows,  consisting  of  greater  numbers,  and  somewhat  irregularly  arranged ;  the 
poriferous  zones  are  narrow  and  depressed,  and  follow  the  flexures  of  the  areas ;  the  pores 
are  round,  closely  situated,  and  disposed  obliquely ;  there  are  eighteen  pores  (thirty-six 
in  aU)  opposite  one  of  the  largest  plates ;  the  interambulacral  areas  are  very  wide, 
five  to  six  plates  in  a  column ;  the  areolas  are  wide,  slightly  oval  (the  minor  axes  being 
towards  the  poles)  at  the  ambitus,  circular  at  the  peristome  and  anal  margins,  and  are 
svu-rounded  by  an  undercut  overhanging  border,  encircled  by  a  series  of  about  twenty 
granules,  each  raised  on  a  distinct  shield-like  maramillated  plate ;  the  areolas  at  the 
equator  have  their  borders  separated  from  the  upper  and  under  plates  by  a  small  interval 
occupied  by  about  five  sets  of  granules ;  at  the  under  surface  these  granules  are  absent, 
and  the  scrobicular  margins  are  in  contact ;  at  the  upper  surface  the  granules  increase  in 
number ;  the  penultimate  plate  of  the  anal  surface  has  an  areola  rather  larger  than  that 
below ;  the  final  plate  has  a  rudimentary  tubercle  in  a  small  circular  areola,  this  last  plate 
is  covered  with  granules ;  the  boss  is  not  prominent,  its  summit  is  smooth  and  without 
crenulation,  the  tubercle  is  moderately  large  and  perforated ;  the  miliary  zone  is  narrow, 
and  the  granules  are  so  arranged  as  to  present  the  appearance  of  radiating  from  the 
scrobicular  margin  towards  the  sutui'es ;  they  are  much  smaller  than  those  surrounding 
the  areolas ;  the  surface  on  which  they  are  studded  dips  towards  the  sutures,  causing  the 
latter  to  be  clearly  defined.  The  apical  disc  is  of  the  same  size  as  the  mouth-opening 
and  in  the  specimen  figured  is  six  tenths  of  an  inch  in  diameter ;  the  plates  with  which 
it  is  furnished  are  large,  and  covered  with  granules  ;  the  mouth  is  furnished  with  strong 
jaws,  shown  in  the  plate. 

"  The  spines  are  long,  cylindrical,  and  very  slightly  tapering,  covered  with  small, 
strong,  equal-sized  granules,  the  points  of  which  project  outwards.  They  are 
arranged  in  ten  regular  longitudinal  ridges,  with  a  sulcus  between  them  covered  with 
a  very  fine  granulation.  The  spiny  granules  continue  to  within  a  tenth  of  an  inch  of  the 
collar ;  the  neck  is  very  short  and  smooth,  the  head  moderately  large,  cone-shaped,  and 
longitudinally  striated  with  numerous  fine  lines  ;  the  rim  of  the  acetabulum  is  very  finely 
crenulated.  The  length  of  the  longest  spine,  that  of  the  ambitus,  is  one  inch  and  eight 
tenths ;  it  is  slightly  broken  at  the  extremity,  and  therefore  would,  if  perfect,  be  rather 
longer ;  its  diameter  is  one  tenth  of  an  inch ;  the  short  spine,  which  is  unbroken  (seen  in 
the  right  hand  of  the  plate),  has  its  extremity  suddenly  expanded. 

"  Affuiliies  and  Differences. — Cidaris  intermedia,  in  the  general  appearance  of  its  test, 
closely  approaches  C.  sceptrifera  and  C.  subvesiculosa ;  it  differs  from  the  former  in  the 
scrobicular  margins  from  the  ambitus  to  the  peristome  being  in  contact,  or  not  separated  by 
more  than  one  granule, — in  the  more  narrow  miliary  zone, — in  the  lesser  number  of  rows 


FROM   THE   WHITE    CHALK.  71 

of  granules  in  the  anibulacral  areas  at  the  ambitus  (C.  scepfriferam  specimens  of  the  same 
size  as  that  under  consideration  having  eight  at  the  equator,  whilst  this  species  has  six), — 
in  these  granules  being  more  irregularly  disposed  and  more  crowded  together, — in  the 
proximal  discal  plate  being  marked  with  a  more  prominent  tubercle,  and  in  its  shape 
being  less  elongated, — in  the  areolas  being  relatively  larger, — in  the  spines  being  uniformly 
cylindrical  instead  of  fusiform,  and  of  much  less  diameter, — and  in  the  serrated  ridges  of  the 
spines  being  fewer,  wider  apart,  and  continuous  the  whole  length,  whilst  in  C.  sceptrifera 
some  of  the  ridges  cease  at  the  widest  part  of  the  spine.  C.  intermedia  differs  from 
C.  mhvesiculosa  in  the  scrobicular  margins  of  adjacent  plates  being  less  widely  separate, 
— in  the  granules  on  the  margins  of  the  areolas  being  more  distant, — in  the  sutures  of 
the  miliary  zones  being  less  marked, — in  the  miliary  zones  being  smaller, — in  the  spines 
being  of  less  diameter,  with  less  numerous  ridges,  and  apparently  shorter  (some 
spines  of  C.  mhvesiculosa,  of  a  test  of  equal  dimensions,  reaching  a  length  of  three  inches), 
— and  in  the  plates  presenting  a  flatter  and  less  tumid  appearance. 

"  Locality  and  Strati  graphical  Poszif/ow.— Collected  from  the  White  Chalk  of  Sussex, 
apparently  from  the  base  of  the  Chalk-with-fiints ;  rare.  The  specimen  figured,  Plate  XII, 
fig.  1  a,  is  of  the  natural  size.  Fig.  1  h,  one  of  smaller  spines  magnified,  length  1  inch, 
diameter  ^th  of  an  inch. 

"Additional  Notes  on   CIDABIS  CLAVIGUBA,  Koniff.     (Seep.  48.) 

"  Very  marked  as  are  the  variations  in  the  general  aspect  of  the  spines  of  C.  clavigera, 
it  will  usually  be  found  that  a  single  and  prevailing  form  is  connected  with  each  indivi- 
dual test.  On  PL  XIII  are  drawn  the  tests  and  spines  (figs.ll  a,  3  a,  4  a)  of  three  speci- 
mens, in  which  the  spines  attached  to  the  tests  are  tolerably  uniform  in  shape  in  each  case 
collectively,  yet  are  dissimilar  when  viewed  by  groups,  those  of  fig.  I  a  being  all  cla- 
viform,  those  of  fig.  3  a  being  all  medially  constricted,  those  of  fig.  4  a  being  all  fusiform. 
The  same  remark  holds  good  in  other  examples  not  drawn  on  the  plate.  I  have  now 
before  me  sixteen  specimens  of  C.  clavigeru,  with  the  spines  attached,  in  all  of  which  speci- 
mens, although  as  a  general  character  each  company  of  spines  has  a  club-shaped  or  approxi- 
mately club-shaped  contour,  there  is  so  great  a  variableness  among  the  different  groups 
that  if  in  any  group  the  two  extremes  in  form  were  to  be  compared  apart  from  the  test 
they  could  easily  be  mistaken  for  different  and  distinct  species ;  some  (No.  1  of  the  Table 
on  page  72)  being  wholly  cylindrical,  these  by  easy  gradations  seen  in  sets  of  forms  passing 
on  so  as  to  become  pear-shaped  (No.  4),  next  taking  up  the  ordinary  clavigerous  type 
(Nos.  6,  7,  S),  and  ending  with  those  having  the  medially  constricted  outline  (No.  10). 

"  I  append  woodcuts  of  some  of  these  varieties,  giving  their  dimensions  in  tenths  of 
an  inch,  and  also  the  diameter  (major  axis)  of  the  test  to  which  they  belong.  The 
measurements  of  the  spine  in  each  case  have  been  derived  from  a  specimen  which  in  its 
natural  position  would  have  been  affixed  to  the  ambitus. 


72 


CIDARIS 


"  Table  showing  variation  of  form  in  the  spines  of  Cidaris  dav'igera. 


Total 


Ambitus   Spine,  characteristic  of  the    .       ,,      . 
1    !•  ,-1        11       /-  .1      lenprth  of 


general  form  of  the  wliole  of  Ilie 
spines  attached  to  any  individual 
test  of  C.  clavigera,  nat.  size 


Almost  unif'oimly 
cylindrical  raid 
slender;  very  un- 
usual form  of 
spine. 

1. 


iiii' 


Almost     unifornilv 

cvlindrical,      bnt     'iiilll 

i  '  •  • ! ;^ 

not  slender;  very 


•iili^l 


Sliglillj'     tapering ; 
rare. 

3. 


Pear-sliaped,  longi- 
tudinal section 
elliptical ;  rati  er 

rare. 

4. 


Pear-sbaped,  longi- 
tudinal section 
ovate;  rather 

rare. 


longest 

ambitus 

spine. 


Diameter 

of  spine  at 

neck. 


M 


Diameter 

at  greatest 
thickness. 


Length  of 
neck  before 

swelling 
commences. 


■3 


Form  of  apex. 


Hemisphe- 
rical. 


Hemisphe- 
rical. 


Subacute. 


Subacute. 


Sub-beniisplie- 
rical. 


Diameter  of  test 
at  ambitus. 


Uncertain, 
about  I'O 


Uncertain. 


About  'G 


I-l 


1-2 


FROM  THE  WHITE  CHALK. 


73 


"  Table  showing  variation  of  form  in  the  spines  of  Cidaris  davigera — continued. 


Ambitus  Spine,  characteristic  of  tlie 
general  form  of  tlie  whole  of  the 
spines  attached  to  any  individual 
test  of  C.  clavigera,  nat.  size. 


Club-shaped,    stem 

slightly  tapering ;      v. .m 
common. 
6. 


Club-shaped,    stem     (illji 
cylindrical;  com-      "*'*' 
mon. 
7. 


Club-shaped,     por-  (■(iiiij 
tion   nearest  the 


apex  constricted ; 
common. 
8. 


Club-shaped,     por- 
tion nearest  the 
apex  constricted ; 
rather  rare. 
9. 


Constricted  at  about 
half  the  length;     U|.(jj 
very  rare. 
10. 


Total 

length  of 

longest 

ambitus 

spine. 


1-3 


1-0 


1-3 


1-0 


Diameter 

of  spine  at 

neck. 


Diameter 
at  greatest 
thickness. 


Length  of 
neck  before 

swelling 
commences 


Form  of  apex. 


Hemi- 
spherical. 


Hemi- 
spherical. 


Hemi- 
spherical. 


Hemi- 
spherical. 


Acute. 


Diameter  of  test 
at  ambitus. 


About  rO 


1-1 


11 


10 


74- 


CIDARIS 


"  From  the  above  Table  it  will  be  seen  that  this  variation  in  form  is  independent  of  the 
size  of  the  test,  and  is  dependent  rather  npon  some  peculiar  law  in  the  formation  of  the 
spine,  or  some  cause  which  has  contributed  to  produce  a  greater  development  of  calcareous 
matter  in  one  part  than  in  another.  In  flints  which  contain  the  spines  of  C.  cla- 
vigera  a  fracture  passing  through  the  spine  will  often  exhibit  this  growth  very  beauti- 
^^'^^  1-  fully;  thus,  in  the  woodcuts  (fig.  1),  whilst  an  earlier  form  of 

the  spine  is  clearly  defined,  the  subsequent  addition  of 
material  is  also  manifested  by  the  change  of  tint.  The  same 
efiect  can  also  be  observed  in  longitudinal  sections  of  the 
ordinary  spines,  a  difi'erence  of  density  and  of  hardness  in 
the  whole  or  parts  of  the  enveloping  layers  being  very 
apparent. 

Sections  of  body-spines  of  C.clmigera 
in  flint. 

"  In  C.  claviffera  the  difi'erence  between  the  spines  of  the  peristome  and  of  the  ambitus  is 
more  marked  than  in  most  of  the  other  species  of  the  Cidarid^  of  the  Upper  Cretaceous 
group.  The  woodcuts  (fig.  2)  drawn  from  the  spines  of  the  tubercles  adjacent  to  the 
mouth,  and  magnified  four  diameters,  show  that  their  apex  is  more  acute,  their  ridges  fewer, 
and  their  body  more  elongate-ovate  than  in  the  larger  spines  of  the  ambitus.  The  spines 
of  the  granules  (fig.  3)  are  also  dissimilar,  being  longitudinally  striated,  contracted  at 
intervals,  having  almost  parallel  sides,  and  being  in  transverse  section  ovate. 


Fig.  2. 


Spines  of  C.  clavigera  from  tlie  tubercles  aiijacent  to  the  peristome ; 
magnified  four  diameters.  One  spine  lias  four  sen-ated  ridges, 
tiie  other  six. 


Fig.  3. 


Spine  of  C.  clavigera  from  tlie  granules  on  the 
margin  of  the  ambulacral  areas ;  magnified 
eight  diameters. 


"  The  spines  in  their  original  condition  appear  to  have  been  tinted  with  parallel  bands 
of  colour,  perpendicular  to  the  axis.  In  several  examples  now  in  my  cabinet  the  apex  of 
the  spine  shows  evidence  of  this  peculiarity  ;  but  in  one  specimen  in  particular  (a  test  to 
which  the  spines  are  attached)  that  circumstance  is  so  marked  and  is  so  persistent  (the 
base  and  apex  of  the  body  of  the  spines  being  specially  affected)  that  it  can  hardly  be  the 
result  of  accident. 

"  The  common  longitudinal  perforations  in  the  outer  layer  of  the  spine  alluded  to  at 
p.  50  seem  to  have  been  chiefly  due  to  disease  or  to  some  difi'erence  in  structm-e  which 
caused  those  parts,  now  empty,  to  decay  with  greater  facility  in  one  direction  than  in 


FROM  THE  WHITE  CHALK.  75 

anotliei".  A  transverse  section  of  spines  so  affected  proves  that  the  canals  are  of  neither 
uniform  length  nor  dimensions,  some  being  of  greater  extent  and  more  open  than 
others . 

"  The  central  perforation  not  unusual  at  the  apex  of  some  spines,  seems  also  due  to 
disease  or  to  parasitic  borings,  and  will  often  be  found  to  extend  downvi^ards  as  far  as 
the  acetabulum.  This  is  the  case  with  the  spine  drawn  in  PI.  V,  fig.  6.  A  portion  of  the 
surface  of  this  spine  having  been  cai'efully  removed  subsequent  to  the  drawing  being  made  on 
the  plate,  the  cavity  apparent  at  the  apex  was  seen  to  extend  through  the  whole  length  of 
the  body,  unaltered  in  size ;  just  below  this  point  it  suddenly  contracted  in  a  circular 
curve  (similar  to  the  base  of  the  perforations  made  by  a  Pholas)  as  though  to  avoid  break- 
ing through  the  walls  of  the  neck ;  at  the  lower  point  of  the  circular  excavation  the  opening 
appeared  again,  only  with  a  very  much  less  diameter,  and  extended  as  far  as  the  articular 
cavity,  through  which  it  passed.  Another  spine  open  at  the  apex,  when  cut  lengthways, 
gave  the  same  result  (of  a  continuous  tube,  of  two  different  diameters),  except  that  the 
opening,  which  extended  almost  as  far  as  the  acetabulum,  did  not  pierce  it,  but  passed 
outwards  in  a  transverse  direction. 

"  The  test  of  C.  davigera  varies  in  the  proportions  of  its  parts  from  youth 
to  age ;  my  smallest  example,  five  tenths  of  an  inch  in  width,  differs  consider- 
ably in  appearance  from  my  largest,  which  is  one  inch  and  seven  tenths  in 
width.  Comparing  these  two  it  is  seen  that  the  tubercles  in  the  former  are 
relatively  larger  than  in  the  latter ;  that  the  granules  of  the  miliary  zone  are  in 
the  former  almost  as  large  as  in  the  latter ;  that  the  number  of  plates  are  the  same 
in  both ;  that  there  is  an  oval  rudimentary  tubercle  in  the  uppermost  plate  of  the 
anal  side  in  the  largest  specimen ;  that  the  areolas  of  the  two  superior  tubercles 
of  the  anal  side  are  in  the  smallest  example  separated  by  only  three  granules,  including 
those  of  the  scrobicular  margin,  whilst  in  the  largest  example  there  are  fourteen.  Both 
specimens  have  four  rows  of  granules  in  the  ambulacral  areas  at  the  ambitus ;  in  the 
smallest  they  are  of  equal  size  and  equally  disposed,  in  the  largest  the  two  interior  are 
much  smaller  than  the  two  exterior,  more  numerous,  and  crowded  together.  These  dif- 
ferences have  a  tendency  to  cause  the  two  specimens,  when  placed  with  the  anal  side 
uppermost,  to  appear  very  dissimilar,  particularly  in  the  region  of  the  miliary  zone. 
Of  these  two  specimens  the  smallest  is  much  below  and  the  largest  much  above  the  average 
size. 

"  Spines  of  C.  davic/era  are  sometimes,  but  very  rarely,  found  as  far  down  as  the 
middle  of  the  flinty  Chalk ;  the  proper  horizon  of  C.  davigera  is  above  this  part. 

"  Figures  1  a,  1  (5,  2,  3  a,  3  (5,  3  <?,  4  a,  ^h,^  a,h  b,  PL  XHI,  are  from  the  Upper 
Chalk  of  Bromley,  in  Kent. 


76  CIDARIS 


"A.DDITIONAL  Note  on   CIDJBIS  FUBOBNJTJ, 'Forbes.     (See  p.  62.) 

"  This  Cidaris  is  the  largest  of  all  the  Cretaceous  Cidarid/e  ;  portions  of  a  full-grown 
specimen  now  before  me,  containing  fom-  complete  columns  of  plates  in  contact,  give  the 
following  dimensions  for  the  test — height,  two  inches  and  two  tenths ;  transverse  diameter, 
two  inches  and  one  tenth.  The  spines,  like  the  body,  also  exceed  those  of  all  other 
species.  In  a  mass  of  spines  of  C. perornata  from  my  cabinet,  which  are  all  one  tenth 
of  an  inch  in  diameter,  is  one  which,  although  deficient  of  a  portion  of  its  apex,  measures 
in  the  remaining  part  of  its  length  four  inches  and  six  tenths — this  length  is  by  no  means  a 
maximum.  The  number  of  the  plates  and  the  form  of  the  spines  appear  to  have  rendered 
perfect  examples  of  the  test  with  spines  attached  exceedingly  rare.  Separate  plates  and 
groups  of  broken  spines  are  plentiful ;  complete  columns  of  plates  uncommon.  Small 
Ostrece  are  occasionally  found  affixed  to  the  spines. 

"  The  test,  when  full-grown,  has,  in  the  ambulacral  areas,  eight  rows  of  granules  at  the 
ambitus ;  of  which  rows  the  two  exterior  are  the  largest  and  most  evenly  disposed,  the 
six  interior  are  more  numerous,  of  less  size,  and  not  so  regularly  arranged ;  at  the  mouth- 
opening  there  are  six  rows,  at  the  anal  four ;  the  second  discal  plate  has  nineteen  pairs  of 
pores  in  the  poriferous  zone ;  the  proximal  discal  plate  in  each  column  has  a  rudimentary 
tubercle  and  an  elongate  obsolete  areola.  The  granules  of  the  miliary  zone  are  of  two 
sizes,  the  smallest  of  which  occupy  the  spaces  between  the  largest.  In  specimens  of  the 
test  of  the  usual  size  the  first,  second,  and  third  of  the  plates,  reckoning  downwards  from 
the  anal  opening,  have  the  upper  half  of  the  boss  crenulated.  The  spines  belonging  to 
the  granules  of  the  scrobiciilar  margins  are  flat  and  somewhat  fan-shaped;  they  are 
covered  with  minute  strise,  which  converge  from  the  circular  base  (in  which  there  is  an 
acetabulum)  towards  the  smaller  apex ;  length  two  tenths  of  an  inch,  greatest  width  one 
twentieth.  The  jaws  of  a  full-grown  specimen  do  not  greatly  difier  in  outline  from  those 
of  other  species ;  they  are  half  an  inch  in  length. 

"  Cidaris 2ierornata  is  tolerably  common  in  the  Upper  Chalk;  it  appears  to  commence 
(where  it  is  rare)  in  the  middle  of  the  flinty  Chalk. 


"  Additional  Note  on  CIBABIS  DIXONI,  Cotteau.     (See  p.  07.) 

"  All  the  spines  of  this  species  hitherto  found  are  of  considerable  size,  and  are  clavi- 
form,  and  inflated ;  the  apex  is  acute ;  the  surface  covered  with  numerous  granules,  which 


FROM  THE  GREY  CHALK.  77 

are  large  and  elongate  on  the  upper  half  of  the  body,  pointed  at  the  apical  region, 
circular  on  the  lower  half  of  the  body,  diminishing  in  area  as  they  approach  the  neck, 
and  ceasing  at  that  part,  arranged  in  rows  gradually  increasing  in  number  from 
the  apex  to  the  greatest  diameter,  and  afterwards  more  closely  and  less  regularly 
deposited ;  the  neck  smooth,  short,  and  very  much  contracted  ;  the  milled  ring  is  slightly 
prominent,  covered  with  fine  longitudinal  striaj ;   the  head  smooth. 

"  The  spines  of  C.  Bixoni  occur  at  the  base  of  the  Lower  or  Grey  Chalk  in  the  cliffs 
between  Folkestone  and  Dover,  in  the  band  containing  the  spinous  Ostrea  carinata,  Sow. 
(M.C.,  tab.  365,  fig.  1),  in  company  with  C.  Bowerhankii ;  they  are,  however,  very  rare. 
The  same  species  is  found  occasionally  in  the  "  Coprolilic  Bed  "  of  Cambridge,  a  deposit 
containing  rolled  fossils  from  the  Lower  Chalk,  Upper  Greensand,  and  Gault  formations. 
The  specimen  figured  in  PI.  XH,  fig.  6,  and  obtained  from  the  Coprolitic  Bed  of 
Cambridge,  is  identical  in  all  respects  with  the  Folkestone  examples,  except  that  the 
surface  is  more  worn,  and  appears  to  have  been  subjected  to  much  friction ;  the  width  of 
the  Cambridge  specimen  is  seven  tenths  of  an  inch,  length  of  body  one  inch.  The 
total  length  of  spine  (measured  from  a  specimen  in  perfect  condition  in  my  cabinet), 
from  Folkstone  is  one  inch  and  four  tenths ;  greatest  diameter  (midway  between  apex 
and  edge  of  acetabulum)  seven  tenths ;  length  of  head  and  neck  three  twentieths ; 
diameter  of  neck  three  twentieths. 

"  The  test  of  this  Cidaris  has  not  at  present  been  discovered ;  it  would  appear,  however, 
judging  from  the  analogy  of  its  spines  with  those  of  C.  Bowerbankii,  that  it  must  have 
much  in  common  with  the  latter,  except  size ;  perhaps  it  may  be  an  aged  form  of 
C.  Bowerbankii. 


"  Additional  Note  on  CIDABIS  BOWERBANKII,  Forbes.     (See  p.  45.) 

"  Li  this  species,  as  in  others  of  the  Cidares,  the  form  of  the  spine  varies  according  to 
its  position  on  the  test ;  those  at  the  peristome  are  tolerably  cylindrical,  with  an  acute 
apex ;  those  at  the  ambitus  are  inversely  conical,  with  the  apex  less  acute,  and  those  at 
the  anal  margin  have  the  body  inflated  and  the  apex  somewhat  obtuse.  The  peri- 
stome spines  have  the  surface  covered  with  coarser  granulations  than  is  the  case  with 
those  which  occur  on  the  opposite  side.  At  Southeram  Pit,  near  Lewes,  Sussex  (Lower 
Chalk),  tests  with  the  spines  in  situ  are  occasionally  found.  In  my  cabinet  is  a  specimen 
from  Southeram  Pit  nearly  perfect,  in  which  almost  the  whole  series  of  spines,  from  the 
anal  to  the  oral  region,  are  in  position,  and  in  which  the  variation  of  form  in  these  spines, 
according  to  their  situation,  is  well  exhibited.  From  this  specimen  were  drawn  the  figures 
shown  in  the  woodcuts  fig.  4  a — d,  which  are  twice  the  size  of  the  originals ;  a  is  the  spine 


78 


CIDARIS 


in  connection  with  the  tubercle  adjacent  to  the  anal  margin  ;  b  that  on  the  next  tubercle, 
counting  downwards  ;  c  that  beneath  b  ;  and  c/that  below  c,  on  the  tubercle  which  is  the  third 
from  the  peristome :  a  is  in  length  five  tenths  of  an  inch,  in  diameter  three  tenths  ;  d  is  in 
length  two  tenths  of  an  inch,  in  diameter  one  twentieth.  The  test  from  which  these  spines  are 
derived  is  five  twentieths  of  an  inch  in  height,  and  nine  twentieths  in  transverse  diameter. 

Fig.  4. 


a.  It.  c.  d. 

Spines  of  Cidaris  Bowerhankii ;  magnified  two  diameters. 

"  Several  of  the  spines  of  this  species  from  different  localities  are  figured  on  PI.  XIII ; 
figs.  9,  10,  and  11  are  from  Folkestone,  figs.  13  and  14  from  Cambridge,  S  from  near 
Arundel,  from  which  last-mentioned  locality  also  come  the  plates  of  C.  dissimilifi,  figured 
PL  XIII,  figs.  Q>  a,Qb.  In  all  these  a  certain  variation  in  general  form  is  very  perceptible. 
"  Cidaris  Bowerhankii  has  great  affinities  in  its  test  with  C.  davigera,  but  is  always 
much  smaller  in  size.  It  is  a  very  rare  species.  The  horizon  of  C.  Bowerbankii  at 
Folkestone  is  just  above  the  Upper  Greensand. 

"  At  Folkestone,  in  company  with  the  spines  of  C.  Bowerbankii,  occur  globose  spines 
with  a  short  neck,  and  having  tlie  body  covered  with  coarse  spiny  projections  arranged 
longitudinally.     They  are  drawn  of  the  natural  size  in  the  woodcut  fig.  5 ;  they  appear 
to  differ  from  C.  velifcra,  and  arc  perfectly  distinct  from  the  spines  of  C.  Bowerbankii. 

Fig.  5. 


a.  i.  c. 

Spiues  of  a  Cidaris  from  tlie  Lower  Clialk  at  Folkestone ;  natural  size. 


"  Additional  Note  on  the  CIDARES  from  the  Red  Chalk.     (See  p.  44.) 

"  In  the  thin  red-coloured  band  met  with  at  Hunstanton,  in  Norfolk,  and  in  the  lowest 
of  the  pink-coloured  beds  at  Speeton,  in  Yorkshire,  occasionally  occur  elongate,  cylindrical 


FROM  THE  RED  CHALK.  79 

spines,  which  do  not  exactly  agree  with  those  previously  refeiTcd  to  in  this  Monograph ; 
four  of  these  are  drawn  on  PI.  XH,  of  which  figs.  7,  8,  and  9  are  from  Hunstanton,  and 
fig.  10  from  Speeton.  They  may  be  divided  into  three  classes — (a)  slender,  having  few  (ten 
to  sixteen)  longitudinal  ridges,  with  a  prickly  border,  PI.  XH,  figs.  7  and  9 ;  (/3)  thick, 
having  numerous  longitudinal  ridges,  with  the  prickles  almost  obliterated,  PI.  XH,  fig.  10; 
and  (7)  slender,  without  ridges,  but  with  an  occasional  projecting  prickle. 

"  The  drawing,  PI.  XH,  fig.  7,  represents  a  magnified  view  (the  natural  size  being 
depicted  by  a  black  line)  of  the  expanded  extremity  of  a  spine  with  twelve  ridges,  not 
unlike  in  its  general  character  that  to  be  met  with  in  some  forms  of  the  spines  of 
Cidaris  GauUina,  but  differing  from  the  latter  in  the  valleys  between  the  ridges  being 
covered  with  very  fine  longitudinal  lines,  instead  of  being  marked  with  fine  granulations. 
Fig.  9,  with  ten  ridges,  is  marked  also  by  the  fine  longitudinal  striae,  and  the  absence  of 
granulations  in  the  valleys ;  the  lines  of  spiny  projections  or  prickles  are  thinner,  more 
conspicuous,  sharper,  and  less  numerous  than  in  the  spines  of  C.  GauUina ;  it  is  very 
slightly  tapering ;  the  fragment  preserved  measures  an  inch  in  length,  and  must  when 
perfect  have  been  at  least  two  inches ;  in  general  aspect  it  bears  a  strong  resemblance  to 
C.  subvesiculosa  from  the  Upper  Chalk. 

"  The  spine  fig.  10  «  (natural  size),  and  fig.  10  1^  (a  portion  magnified)  is  found  both  at 
Speeton  and  Hunstanton ;  the  specimen  figured,  which  was  from  Speeton,  and  is  not 
quite  perfect,  measures  one  inch  and  a  half  in  length,  and  is  two  tenths  at  its  greatest 
diameter ;  the  body  of  the  spine  increases  very  gently  in  diameter  for  a  short  distance 
from  the  acetabulum,  and  then  as  gently  diminishes  j  the  margin  of  the  acetabulum  is 
crenulated,  a  double  milled  ring  surrounds  the  head,  the  neck  is  short  and  smooth,  and 
the  body  is  marked  by  about  thirty  longitudinal  ridges,  which  are  crowned  by  small  and 
obtuse  spiny  projections.  The  valleys  between  the  ridges  are  covered  with  fine  longi- 
tudinal striae;  the  general  aspect  is  that  of  a  spine  of  C.  dissimilis,  but  the  latter 
generally  has  the  spines  much  more  slender. 

"  Fig.  8,  from  Hunstanton,  is  only  a  fragment,  half  an  inch  in  length,  and  one  tenth  of 
an  inch  in  diameter;  it  is  uniformly  cylindrical,  with  the  surface  quite  smtooh  and 
without  stria; ;  arising  from  the  smooth  surface  are  stout  prickles,  like  thorns,  which  are 
repeated  in  longitudinal  lines  at  about  the  distance  of  the  tenth  of  an  inch  apart  from 
each  other.  It  is  a  very  peculiar  spine,  totally  distinct  from  all  those  of  the  Cretaceous 
species,  and  mostly  resembles  the  spine  of  C.  perornala  from  the  Upper  Chalk ;  in  the 
latter,  however,  the  prickles  arise  from  a  small  longitudinal  ridge,  and  are  not  isolated  and 
unconnected.  The  same  form  of  spine  occurs  at  Speeton.  In  the  ratio  of  frequency, 
the  form  a  is  more  common  than  that  of  /3 ;  and  the  forms  a  and  /3  are  more  conunon 
than  that  of  7,  which  is  very  rare." 


80  CLASSIFICATION  OF  THE. 

Tamilij  2. — HEMiciDARiDiE.     (Not  yet  found  hi  British  Cretaceous  strata.) 

Family  3. — DiADEMADiE. 

This  Family  inchides  large  and  small  Urchins  having  a  thin,  circular,  pentagonal,  and 
subpentagonal  test,  more  or  less  depressed  on  the  upper  surface,  and  flat  at  the  base. 

The  ambulacral  areas  are  wide  and  straight,  with  two  rows  of  primary  tubercles,  often 
as  large  and  numerous  as  those  of  the  inter-ambulacral  areas. 

The  poriferous  zones  are  narrow,  almost  always  straight,  and  sometimes  subflexuous ; 
the  pores  are  unigeminal^  bigeminal,  and  trigeminal  in  their  arrangement  in  different  genera. 

The  inter-ambidacral  areas  are  in  general  twice  the  width  of  the  ambulacral,  and  occu- 
pied, at  the  equator,  with  two,  four,  six,  or  eight  rows  of  primary  tubercles,  which  diminish 
gradually  in  numl)er  near  the  poles.  The  bosses  of  all  the  tubercles  are  small ;  their 
summits,  in  general,  are  crennlated,  sometimes  uncrenulated ;  the  tubercles  are  small,  in 
general  perforated,  in  Cypliosoma  imperforate  ;  they  are  in  general  a  little  larger  than  those 
of  the  ambulacra;  but  are  often  of  equal  magnitude  in  both  areas. 

The  apical  disc  is  small,  and  situated  opposite  to  the  mouth  ;  it  is  composed  of  five 
ovarial  and  five  ocular  plates ;  the  anterior  pair  of  ovarial  plates  are  a  little  larger  than 
the  posterior  pair,  and  the  right  antero-lateral  plate,  with  a  small,  spongy,  madreporiform 
body  on  its  upper  surface,  is  the  largest ;  the  vent  is  round  or  oblong,  and  generally  in 
the  centre  of  the  disc ;  the  ocular  plates  are  very  small,  and  distinguished  with  difficulty. 

The  mouth-opening  is  in  general  large  and  decagonal,  and  the  peristome  divided  into 
ten  lobes  by  deep  notches  ;  the  jaws  in  general  are  large  and  powerful. 

The  spines  in  existing  genera  are  long,  slender,  and  tubular,  sometimes  three 
times  as  long  as  the  diameter  of  the  test.^  In  the  fossil  extinct  genera  they  rarely  attain 
the  length  of  the  diameter  of  the  test,  and  are  short,  stout,  and  solid,  except  in  Hemipedina, 
which  have  long  hair-like  spines.  The  long  tubular  spines  of  living  Diademas,  and  a  rare 
form  from  the  Cretaceous  rocks,  are  encircled  by  spiral  verticellate  processes,  or  fringe- 
like scales,  PI.  XIV,  fig.  2,  whilst  the  surface  of  the  solid  spines  of  Pseudodiademas  is  in 
general  covered  with  fine  longitudinal  lines ;  neither  prickles  or  asperities  being  developed 
on  their  stems. 

Lamarck  divided  the  genus  Cidaris  of  Klein  into  two  sections,  "  Les  Turbmis"  and  "  Les 
Diadhnes  "  these  were  afterwards  by  Dr.  Gray"  erected  into  genera ;  the  Cidaris  radiata, 
Leske,  constituting  a  third  type,  formed  his  new  genus  Astropyya.  The  genus  Cidarifes  of 
Lamarck  was  considered  to  form  a  natural  family,  including  the  genera  Cidaris,  Biadema, 
and  Astropyya,  which  he  constituted  and  characterised  thus  : — 

1  Peteks,  '  Ueber  Gruppe  der  Diademen,'  p.  2,  101.  Konigl.  Akademie  der  Wissenchaften  Augt., 
1853,  BerUn. 

-  '  Annals  of  Philosophy,'  new  series,  vol.  s,  p.  426,  1825.  "An  attempt  to  divide  the  Echinidae  or 
Sea-Eggs  into  natural  families." 


DIADEMAD^..  81 


1.  Famili/ — Cidarid^.     Cidurites,  Lamarck. 

Body  with  spines  of  two  sizes;   larger  ones  either  club-shaped  or  very  long;   spine- 
bearing  tnbercles  perforated  at  the  summit. 


Genus  1 — Cidaris,  Klein,  Lamarck.     (Les  Turbans.) 

Body  depressed,  spheroidal ;  ambulacra  waved ;  small  spines  compressed,  two-edged, 
two-rowed,  covering  the  ambulacra,  and  surrounding  the  base  of  the  larger  spines. 

This  genus  may  be  divided  according  to  the  form  of  the  larger  spines :  the  extra- 
ambulacral  beads  have  only  two  rows  of  spines. 

Cidaris  impekialis,  Lamh.     Klein.,  Nat.  dispositio  Echinodermatum,  tab.  vii,  fig.  a. 


Genus  2 — Diadema,  Gray.     (Les  Diademes.) 
Body  orbicular,  rather  depressed  ;  ambulacra  straight ;  spines  often  fistulous. 

EcHiNOMETKA  SETOSA,  Rumph.     Leske,  Klein.,  Nat.  disp.  Ecbinid.,  tab.  .xxxvii,  fig.  1,  2. 
Echinus  diadema,       Linn.     Syst.  Nat.,  by  Turton,  vol.  iv,  p.  139. 
—     CALAMAEIA,     Pallas.     Spicil.  ZooL,  tab.  ii,  fig.  4 — 8. 


Genus  3 — AsTRorvGA,  Grai/. 

Body  orbicular,  very  much  depressed  ;  ambulacra  straight ;  ovarial  scales  very  long, 
lanceolate ;  beads  with  several  series  of  spines. 

Cidaris  uadiata,  Leske,  apud  Klein,  tab.  xliv,  fig.  1. 

The  veiy  meager  characteristics  by  which  Dr.  Gray  has  defined  the  last  two  genera 
merely  shows  that  a  difference  exists,  and  his  description  is  insufficient  for  a  correct  dia- 
gnosis of  either ;  hence  the  various  opinions  extant  regarding  the  character  and  limits  of  his 
genus  Diadema;  only  one  of  the  species  enumerated  as  types,  Diadema  setosa,  Rumph., 

11 


83 


CLASSIFICATION  OF  THE 


is  admitted  to  be  a  true  Diadema.  The  valuable  memoir  of  Herr  W.  Peters^  has 
removed  some  of  the  difficulties  that  surrounded  this  subject,  and  his  grouping  of  the 
living  Diademas  makes  an  important  step  towards  a  natural  classification  of  one  section  of 
this  Family.  Although  the  present  state  of  our  scientific  knowledge  of  the  Diadeniadts 
may  be  considered  as  transitional  rather  than  positive,  still  we  possess  enough  to  justify 
the  separation  of  fossil  Diademas  from  existing  genera,  as  proposed  by  M.  Desor." 

The  DiADEMADiE,  in  fact,  appear  to  consist  of  two  types ;  one  of  these,  with  a  few  rare 
exceptions,  appertains  to  the  present  epoch,  the  other  existed  diu'ing  the  deposition  of  the 
Secondary  and  Tertiary  rocks.  The  living  forms  arc  in  general  large,  depressed  Urchins,  with 
thin  shells,  having  the  tubercles  and  pores  variously  arranged  in  the  different  genera.  They 
have,  in  general,  very  long,  slender,  tubular  spines,  and  the  surface  of  the  stem  is  covered 
with  oblique  annulations  of  small  imbricated  scales.  The  fossil  species,  on  the  contrary, 
are  smaller  Urchins,  with  a  thicker  test ;  having  the  tubercles  and  pores  variously  disposed 
in  different  genera;  the  spines  rarely  attain  the  length  of  the  diameter  of  the  test; 
they  are  in  general  solid,  cylindrical,  sometimes  flattened  or  awl-shaped,  and  their  surface 
is  covered  with  fine  longitudinal  lines.  I  propose  to  include  the  following  genera  in  this 
natural  family. 


A  Table  shoimng  the  Classification  of  the  Diademada. 

Section  a. 
/  Spines  very  long,  slender,  tubular, 


DIADEMAD^  / 


\ 


covered  with  oblique  annulations 
of  imbricated  scales.  Living  in 
tropical  seas. 
A  few  annulated  tubular  .spines  are 
found  iu  the  Upper  Chalk  and  in 
the  Coralline  Crag. 

Section  b. 

Spines  short,  slender,  solid  ;  surface    \ 
covered    with    fine    longitudinal 
lines. 

E.xtinct ;  found  in  the  Oolitic,  Cre- 
taceous, and  Tertiary  Rocks. 


DiAUEMA,  Gray. 
Savignya,  Desor. 
AsTROPYGA,  Gray. 
EcHiNOTiiEix,  Peters. 


PSEDDODIADEMA,  Desor. 

CyPHOSOMA,  Agassi:. 
Hemipedina,  Wriyht. 

Pedina,  Ayassiz. 
EciiiKOPsis,  Ayassiz. 


My  learned  friend  M.  Cotteau,''  in  his  classical  work  on  the  Echinidae  of  France,  has 
lately  proposed  an  extended  classification  of  the  family  Diademad^,  a  resume  oi  which  I 

1  '  Ueber  die  Gruppe  der  Diademen,  Konigl.  Akademie  der  Wissenschaften,'  Berlin  Aug.,  1853. 

-  '  Synopsis  des  Echinides  Fossiles.' 

^  '  Paleontologie  Eranoaise,  Terrain  Cre'tac^,'  tom.  vii,  p.  3"1. 


DIADEMAD^.  S3 

herewith  subjoin;  the  genera  referred  to  this  family  arc  divided  into  four  groups, 
based  upon  the  structure  of  the  tubercles,  whether  they  are  perforated  or  not  perforated, 
and  crenulated  or  not  crenulated. 

In  the  CiDARiDiE  these  characters  have  not  much  significance,  and  are  present  or 
absent  in  many  species  of  congeneric  forms  ;  in  the  Diademadjs,  however,  they  arc  more 
stable  and  persistent,  and  have  served  to  form  a  great  number  of  genera.  If  from  an 
organic  point  of  view  this  structure  of  the  tubercles  is  only  of  secondary  importance,  in  a 
palscontological  sense  it  affords  a  character  which  is  readily  seen,  and  nearly  always 
Avell  preserved. 

The  first  group  comprehends  the  DiADEjiAOiE^  with  tubercles  perforated  and  crenu- 
lated :  Hemicidaris,  Agassiz ;  Acrocidaris,  Agassiz ;  Pseudodiadeina,  Desor ;  Biadema, 
Gray ;  Hibertta,  Michelin ;  Microdiadcma,  Cotteau ;  Heterodiadema,  Cotteau ;  Asfero- 
cidaris,  Cotteau ;   Gl^phoct/phiis,  Haime. 

The  second  group  includes  the  genera  with  tubercles  perforated  and  not  crenulated  : 
Cidaropsis,  Cotteau  ;  Diademopsis,  Desor ;  Ilemipedina,  Wright ;  Ecliinopsis,  Agassiz  ; 
Orthopsis,  Cotteau :  Pedinojjsis,  Cotteau. 

The  third  group  is  destined  to  receive  thegenera  which  have  the  tubercles  imperforated 
and  crenulated  :  Ci^j^hosoma,  Agassiz  ;  Mkropsis,  Cotteau ;  Temnopleurus,  Agassiz  ;  Eclii- 
nocijphns,  Cotteau. 

The  fourth  and  last  group  contains  the  genera  with  tubercles  imperforated  and  uncre- 
nulated  :  Goniopygu3,h.^2&^\z;  Acropelils,  k^^?&VL;  Zeiosoma,  Cotieaii;  Uc/iinocidans,Des- 
moulins ;  Codopleunis,  Agassiz  ;  Kmraiaphorus,  Michelin  ;  Codiopsis,  Agassiz  ;  Cottaldia, 
Desor ;  Magnosia,  IVIichelin ;   Gli/jjficus,  Agassiz ;  TemnecJdnus,  Forbes  ;  Opechinus,  Desor. 

The  genera  which  compose  these  four  groups  are  distinguished  by  straight  or  flexuous 
ambulacra,  the  disposition  of  the  tubercles,  the  structure  of  the  apical  disc,  the  sutural 
and  angidar  impressions  which  mark  the  ambulacral  and  inter-ambulacral  plates,  the 
comparative  width  of  the  peristome,  and  the  form  and  structure  of  the  spines. 

The  following  table  contains  a  definition  of  the  opposable  characters  of  the  thirty -one 
genera  composing  the  family  DiADEMADyE. 

^  In  my  classification  of  the  Eciiiniu/E  I  have  separated  Hemicidaris  and  Acrocidaris  as  a  distinct 

family,  the  Hemicidakid/E. 


84 


CLASSIFICATION  OF  THE 


A.  Tubercles  crenulated  and  perforated. 

a.  Ambulacral  areas   subflexuou?,  provided  witb  large  tubercles  at  the 

ambitus  aud  inferior  surface  .... 

b.  Ambulacra  straight,  provided  witb  tubercles  in  all  their  extent. 

X.  Ambulacral  and  inter-ambulacral  plates  -without  angular  impressions. 
X.  Inter-ambulacral  areas  subgranular  as  they  approach  the  summit. 
y.  Apical  disc  subpentagonal,  peristome  large. 
r.  Each  of  the  ovarial  plates  of  the  apical  disc  carry  a  large  tubercle 
zz.  Apical  disc,  without  a  large  tubercle  on  its  ovarial  plates. 

1 .  Poriferous  plates  unequal  and  irregular. 

If.  Spines  solid,  aciculated,  striated 
ifiip.  Spines  tubular,  verticillated 

2.  Poriferous  plates  straight,  equal,  regular 

)jy.  Apical  disc  narrow,  annular,  peristome  reentrant 

yyy-  Apical  disc  elongated,  prolonged  into  the  middle  of  the  single  inter- 
ambulacral  area ;  peristome  narrow 

xx.   Inter-ambulacra  smooth  near  the  summit,  and  presenting  a  stellate 
appearance     ..... 

XX.  Ambulacral  aud  inter-ambulacral  plates  marked  with  angular  impressions 


Hemicidauis. 


.\CROCIDAKIS. 


PSEUDODIADEMA. 
DiADEMA. 

HiBERTIA. 

MiCRODIADF.MA. 

IIeterodiadema. 

asteeiocibaeis. 
Glypiiocyphus. 


15.  Tubercles  perforated  and  not  crenulated. 

(I.  Ambulacra   subflexuous,   provided  with   tubercles  only  towards   the 

ambitus  and  inferior  surface  ....     Cidakopsis. 

//.  Ambulacra  straight,  provided  with  tubercles  in  all  their  extent. 

X.  Pores  simple  near  to  the  summit. 

X.  Ambulacral  plates  unequal,  irregular. 

//.  Apical  disc  largely  developed,  peristome  wide. 

:.  Miliary  zone  extended;  principal  inter-ambulacral  tubercles  very  large, 

placed  on  the  external  border  of  the  plates     .  .  .     Diadl.moi'SIS. 

t.-.  Miliary  zone  narrower,  tubercles  tolerably  large  and  placed  in  the  middle 

of  the  plates.  .....     Hemipedina. 

yy.  Apical  disc  narrow,  peristome  slightly  developed,  tubercles  very  small .      Echi.nopsis. 
XX.   Ambulacral  plates,  straight,  regular,  sutures  very  apparent  .  .     Orthopsis. 


.\x.  Pores  in  double  series  at  the  superior  surface  and  towards  the  ambitus 


Pedinopsis. 


DIADEMAD.E.  85 

0.  Tubercles  not  perforated  and  crenulated. 

a.  Ambulacral  and  inter-arabulacral  plates  without  angular  impressions. 

X.  Form  depressed,  tubercles  rather  large,  peristome  widely  open      .  .     Cypiiosoma. 

-xx.  Form  inflated,  tubercles  small,  peristome  narrow         .  •  •     Miceopsis. 

h.  Ambulacral   and   inter-ambulacral   plates  marked  with  angular,  and 
sutural  impressions. 

X.  Apical  disc  sub-circular,   inter-ambulacral   tubercles   forming   many   rows 

towards  the  ambitus       .....     Temnopleurus. 

XX.  Apical  disc  pentagonal,  inter-ambulacral  tubercles  forming  two  rows  .     Echinocyphus. 

D.  Tubercles  not  perforated  and  not  crenulated. 

a.  Ambulacral  and  inter-arabulacral  plates  without  angular  and  sutural 
impressions. 

X.  Apical  disc  smooth,  ovarial  and  ocular  plates  perforated  below  at  their  ex- 
ternal angle    ..•■••     Goniopygus. 

XX.  Apical  disc  furnished  with  a  large  tubercle  on  each  ovarial  plate ;  ovarial 

and  ocular  plates  perforated  at  some  distance  from  the  border       .     Acropeltis. 

XXX.  Apical  disc  granular,  deprived  of  tubercles ;  ovarial  and  ocular  plates  per- 
forated at  some  distance  from  the  border. 

X.  Tubercles  rather  large,  forming  regular  vertical  rows. 

y.  Two  rows  only  of  inter-ambulacral  tubercles  ;  mammelon  large  and  pro- 
minent ......     Leiosojia. 


II'J- 


More  than  two  rows  of  inter-ambulacral  tubercles  ;  mammelon  small  .     Eciiixocijjauis. 


yyy.  Inter-ambulacral  tubercles  not  extending  above  the  ambitus  ;  inter- 
ambulacral  area  forming,  at  the  upper  part,  a  depressed  zone, 
perfectly  circumscribed. 

C-.  Four  rows  of  inter-ambulacral  tubercles  towards  the  ambitus  .     C(ELOpleuuus. 

".  Two  rows  of  inter-ambulacral  tubercles  towards  the  ambitus ;  spines 

long,  sub-tricarinated,  and  slightly  bent         .  .  .     K.euaiapiiokus. 

yyyj-  Ambulacral  and  inter-ambulacral  tubercles  limited  to  the  inferior  sur- 
face, replaced  above  the  ambitus  by  caducous  granules  .  .     Codiopsis. 

XX.  Tubercles  small,  forming  very  regular  horizontal  rows. 

y.  Peristome  small,  pores  simple  towards  the  ambitus  .  .     Cottaldh. 

>j>j.  Peristome  very  wide,  sub-pentagonal,  pores  forming  double  rows  from 

the  ambitus  to  the  moulh  ....     Macnosia. 


86  PSEUDODIADEMA 

D.  Tubercles  not  perforated  and  not  crenalated — continued. 

yyy.  Inter-ambulacral  tubercles  irregularly  arranged  above  the  ambitus,  often 

lacerated       ......     Glypticcs. 

h.  Arnbiilacral  and  inter-ambulacral  plates  provided  with  angular  and  sutural 
impressions. 

,x.  Impressions  angular  .....     Temkecuixl'S. 

XX.  Impressions  sutural,  and  angular,  and  much  more  defined       .  .     Opecuis'US. 

The  stratigraphical  (li.-;tribution  of  the  Diadeniadse  extends  from  the  Trias  to  the 
modern  epoch,  where  a  few  species  now  live  in  tropical  seas.  Of  the  thirty-one  genera 
enumerated  in  the  above  table,  seven  are  proper  to  the  Oolitic  period :  Microdiadema, 
Aakrocidarlx,  Cidaropsis,  Heiuipedlna,  AcropeUin,  GlypticMS.  Seven  to  the  Cretaceoas 
period :  Ileterodiadema,  GlyphocyphuH,  Orlhopsiis,  Pedinopsix,  Echinoci/phm,  Leisoma, 
Codiojjsis.  Five  are  special  to  the  Tertiary  period :  Jlibertia,  Echinojms,  Cceloplevrm, 
TemnecJdnm,  OpecJdnus.  Three  to  the  jNIodern  period :  Diadema,  Echinocidaris,  and 
Karaiaphorus.  One  genus,  Pneudodiadema,  is  common  to  the  Oolitic,  Cretaceous,  and 
Tertiary  periods.  Three  genera  are  found  in  the  Oolitic  and  Cretaceous  periods ;  Ilemi- 
c2V«r/y,  which  commenced  in  the  Trias,  ^croczV/ar/s  and  J/«(7«o*?ff,  but  neither  extend  above 
the  Neocomian.  Four  genera  are  common  to  the  Cretaceous  and  Tertiary  periods : 
Goniopyyus,  Collaldiu,  Cyphosoma,  and  Micropms.  The  genus  Temnopleurm  appeared 
in  the  Tertiary  period  and  exists  in  our  present  seas. 


PsEUDODiADEMA,  Desor.  1854. 

This  genus  is  composed  of  small  Urchins  with  a  moderately  thick  test,  which  rarely 
attiiins  two  inches  in  diameter ;  the  ambulacral  areas  in  general  arc  one  third  or  even  one 
half  the  width  of  the  inter-ambulacral  areas ;  the  primary  tubercles  of  both  areas  are 
perforated,  and  nearly  all  of  the  same  size ;  the  bosses  are  small,  and  have  sharply  crenu- 
lated  summits. 

The  ambulacral  areas  have  two  rows  of  tubercles;  the  inter-ambulacral  areas  two 
rows  only,  or  two  rows  of  primary  and  two  or  four  short  rows  of  smaller  secondary 
tubercles,  or  they  have  four,  or  six  rows  of  nearly  equal-sized  primary  tubercles  at  the 
ambitus. 

Tlie  ])oriferous  zones  in  general  are  narrow  and  straight ;  the  pores  in  one  section  are 
unigcniinal  throughout,  and  in  another  they  are  bigeminal  in  the  upper  part  of  the  zones. 
The  apical  disc  is  small ;  and  the  anterior  ovarial  plates  are  larger  than  the  posterior  pair. 

The  motith-opening  is  large,  the  [)eristoine  deeply  notched,  and  the  oral  lobes  are 
nearly  equal. 


FROM  THE  LOWER  GREEXSAND.  87 

The  spines  rarely  attain  the  length  of  the  diameter  of  the  test ;  in  general  they  are 
much  shorter,  cylindrical,  or  needle-shaped,  and  have  a  prominent,  milled  ring  near 
the  articulating  head  ;  the  rim  of  the  acetabulum  is  crenulated,  and  the  socket  perforated ; 
the  surface  of  the  stem  is  sculptured  with  delicate  longitudinal  lines. 

The  Paeudodiademata  are  all  extinct,  and  found  in  the  Liassic,  Oolitic,  Cretaceous  and 
Tertiary  rocks. 

Pfseudodiadema  differs  from  Diadema  in  having  solid  spines,  with  a  smooth  surface, 
the  sculpture,  in  most  cases,  consisting  of  microscopic,  longitudinal  lines;  whilst  in 
Diadeitia  the  spines  are  tubular,  and  have  oblique  annulations  of  scaly  fringes  on  their 
surface.  Pseudodiadema  differs  from  Cyphosoma,  a  Cretaceous  genus,  in  having  the 
tubercles  always  perforated,  those  of  Cyphoxoma  being  imperforate.  It  differs  from 
Hemipedina  in  having  a  small  apical  disc,  and  tubercles  with  crenulated  bosses,  those  of 
Hemijjpdtna  being  smooth ;  and  from  Pedina  in  having  the  pores  unigeminal  or 
bigeminal,  those  of  Pedina  being  arranged  in  triple,  oblique  pairs. 

Pseudodiadema  may  be  divided  into  two  sections,  from  the  different  manner  the 
pores  are  arranged  in  the  zones.  In  one  group  the  pairs  of  pores  form  a  single 
file  throughout;  in  another  the  pores  are  more  numerous,  and  crowded  together  in 
the  upper  part  of  the  zones.  Professor  M'Coy  has  proposed  the  genus  Biplopodia  for 
the  latter.  It  may  be  objected,  however,  that  the  crowding  together  of  a  greater  number 
of  pores  in  a  zone  is,  at  most,  a  sectional  and  not  a  generic  character,  inasmuch  as  the 
arrangement  is  subject  to  great  variation  in  the  diplopodous  species  themselves,  and  is, 
moreover,  often  only  an  adult  development. 


A. — Species  front  the  Lower  Greemand. 
PsErD0Di.\DE3iA  EOTCLABE,  Ago^fsiz.     PI.  XIV,  figs.  3  a,  b,  c. 

DiADEMA  EOTCLAKE,         Ag(u«iz.     M^m.  des  Sc.  nat.  de  Xeuchatel,  vol.  l,p.  139,  tab.  xiv, 

fig?.  10—12,  183C. 

—  —  Bet  Moulin*,  £tiideg  8ar  les  ficliinidei",  p.  316,  No.  2.^,  1837. 

—  OBXATCM,         Jga»n:.     Catal.  SyBt.  Ectyp.  fogs.  Masei  Neoc,  p.  8,  1840. 

—  EOTCLAKE,        JffOMiz.       Dcfcript.  des  lochia,  fois.  de  la  Saitse,  part  2,  p.  4, 

Ub.xvi,  fig.  1—5,  1840. 

—  MACKOSTOMA,  Ayatnz.     Ibid.,  p.  10,  tab.  xvi,  fig.  22 — 26,  1840. 

—  KOTCLABE,        Ag(u*iz  et  Detor.     Catal.  Itaison.  des  Echinides,  Ann.  dc«  Sc.  nat, 

.3e  serie,  t.  vi,  p.  .346,  1846. 

—  MACKOSTOMA,  Jgassiz  et  Beior.     Ibid.,  p.  347,  1846. 

—  —  Bronn.     Index  Palieontologicus,  p.  418,  1846. 

—  COKOXA,  Grot.     OursinB  fosa.  de  rietre,  p.  33,  pi.  i,  fig.  21— 2.3,  1848. 

—  EOTCL.vKE,      Marcou.     Recherch.  geol.  ear  le  Jura  Salinois,  M6m.  Soc.  Geo),  de 

France,  Ire  fserie,  t.  iii,  p.  14.3,  1848. 


88 


PSEl'DODIADEMA 


DiADEMA  llOTULAliE, 

—  MACltOSTOMA, 

—  KOTULAEE, 

DiAPEMA  DUBIUM, 


EOTULAUE, 


PsEUD0UIADE5IA 


B'Orhiyny.    Prod.  dePak'unt.  Strat.,  t.  ii,  p.  89  ;  Et.  17,  No.  489, 

1850. 
D'Orbigny.     Ibid.,  No.  491,  18.".0. 
Cotteau.     Cat.  £cli.  Neocom.,  Bull.  Soc.  de  I'Yonne,  t.  v,  p.  285, 

1851. 
Sharpe.     Sands  and  Gravels  of  Farringdon,  Quart.  Journ.  Geol. 

See,  vol.  X,  p.  194,  1853. 
Foi-bes.     In  Morris's  Catalogue  of  British  Fossils,  2nd  ed.,  p.  76, 

1854. 
Cotteau.    Paleontologie  Francaise,  Ter.  Cretact,  vol.  vii,  p.  422, 

pi.  1097,  figs.  11  —  13;  pi.  1098  and  1099. 
Besor.      Synopsis  des  Echinides  fossiles,  p.  69,  1856. 


—  MACltOSTOMA,       Besor.     Ibid.,  p.  68. 

—  KOTLLAiiE,  Cotteau.    Etudes  sur  les  Echinides  de  I'Yonne,  t.  ii,  p.  24,  pi.  xli.x, 

figs.  1—5,  1857. 

—  piETETi,  Cotteau.     Ibid.,  p.  31,  pi.  I,  figs.  7 — 10,  1857. 

—  TUisERiALE,  Besof.     Synop.  des  Ecliin.  foss.,  p.  445  (Suppl.).  1858. 

—  ROTULARE,  Bujardiii  et  Hufc.     Hist.  Nat.  des  Zoophytes,  Echinoderm.,  p. 

428,  1862. 

—  PERIQUETI,  Biijardiii  et  Hupc.     Ibid. 

—  MACUOSTO.MA,       Bujardin  et  Hupt.     Ibid. 

—  TRISERIALE,  Bujardiii  et  Ilupi-.     Ibid. 


Test  small,  circular,  slightly  pentagonal,  moderately  convex  above,  and  flat  below ; 
poriferous  zones  narrow,  straight ;  pores  in  single  file ;  anibulacral  areas  large,  two 
rows  of  close-set  marginal  tubercles ;  inter-ambulacral  areas,  four  rows  of  tubercles  at 
the  ambitus,  the  outer  rows  disappearing  on  the  upper  surface ;  miliary  zone  wide, 
depressed  near  the  disc,  and  covered  with  an  abundance  of  well-formed  granules.  Mouth- 
opening  large,  decagonal ;  peristome  deeply  notched  ;  lobes  unequal. 

Dimensions. — Height  four  tenths  of  an  inch;  transverse  diameter,  one  inch. 

Description. — This  is  a  very  rare  Urchin  from  the  remarkable  deposit  of  fossiliferous 
sands  and  gravels  near  Farringdon  in  Berkshire,  about  the  age  of  which  so  many  different 
opinions  have  been  given  ;  perhaps  the  Echinidaj  found  therein  may  assist  to  determine  the 
problem  whether  these  beds  belong  to  the  Lower  Greensand,  or  to  a  "  more  modern  member 
of  the  Cretaceous  Series  than  the  Chalk,"  as  maintained  by  the  late  Mr.  Daniel  Sharpe, 
F.G.S.^  The  Diadema  now  before  us  is  a  well-known  and  characteristic  species,  of  the 
middle  stage  of  the  Neocomian  formation,  cQwiwmn^  Echinospatagus  cordiformis ;  and  the 
extensive  table  of  synonyms  prefixed  to  this  article  shows  how  widely  it  is  distributed  in 
beds  of  the  same  age  on  the  continent  of  Europe. 

The  test  is  of  medium  size,  circular  or  slightly  pentagonal,  moderately  convex  on  the 
upper  surface,  and  nearly  fiat  beneath. 

1  "  On  the  Age  of  the  Fossiliferous  Sands  and  Gravels  of  Farringdon  and  its  Neighbourhood,"  '  Quart. 
Journ.  of  the  Geological  Society,'  vol.  x,  p.  176.     1853. 


FROM  THE  LO^^'ER  GREENSAND  89 

The  ambulacra!  areas  are  wide  (fig.  3  a,  b)  and  have  two  rows  of  tubercles  placed  on 
the  margin  of  the  area ;  these  are  small,  uniform  in  structure,  set  closely  together,  and 
gradually  diminish  from  the  equator  to  both  poles ;  a  band  of  granulations  down  the 
middle  of  the  area  divides  the  two  series  from  each  other :  the  poriferous  zones  are  narrow 
and  straight  (fig.  3  b) ;  the  pores  are  round  and  simple,  and  arranged  in  a  single  file 
throughout  the  zones  (fig.  3  c). 

The  inter-am]julacral  areas  are  occupied  at  the  ambitus  by  four  rows  of  tubercles ;  the 
inner  rows  extend  from  the  mouth  to  the  disc,  and  the  outer  rows  diminish  in  size  on 
the  upper  surface  and  disappear  before  reaching  the  disc  ;  the  tubercles  forming  the  inner 
row  are  about  the  size  of  those  in  the  ambulacra ;  those  of  the  outer  row  are  sensibly 
smaller  (fig.  3  b).  The  miliary  zone  is  large,  and  slightly  depressed  near  the  summit ;  it 
is  filled  with  numerous  granules  of  unequal  sizes,  some  of  which  are  mammUlated  and 
perforated ;  the  granules  are  disposed  in  circles  around  the  areolae,  and  fill  the  entire  area 
of  the  zones  with  a  beautiful  oniamentation  ;  the  examples  from  Farringdon  have  lost 
much  of  this  character  from  the  process  of  fossUization  in  those  gravel  beds. 

The  base  of  the  test  is  flat,  and  presents  a  highly  tubercular  surface  (fig.  3  a),  the  foiu* 
rows  of  tubercles  in  the  inter-ambulacral  areas  being  all  distinctly  developed  in  this 
region.  The  mouth-opening,  one  half  the  diameter  of  the  test,  is  proportionally  large : 
the  peristome  is  deeply  notched  into  the  lobes,  the  ambulacral  portions  being  one  half  larger 
than  those  of  the  inter-ambulacral  arches.  In  fig.  3  c,  I  have  given  a  section  of  the 
base,  magnified  four  diameters,  showing  the  relation  of  all  these  parts  to  each  other. 

Affinities  and  Differences. — ^This  Urchin  presents  many  varieties  of  form,  which  have 
been  described  by  difierent  authors  as  so  many  distinct  species,  an  error  that  has  been 
now  corrected,  as  shown  in  the  table  of  synonyms.  It  resembles  P.  Bourgneti,  Ag., 
found  with  it  in  the  same  Xeocomian  beds,  but  is  distinguished  from  that  species 
in  having  the  primary  tubercles  less  developed,  more  closely  set  together,  and  more 
homogeneous ;  and  in  the  secondary  or  outer  series  of  tubercles  being  larger  and  more 
reffularlv  arranged  ;  thev  are,  however,  nearlv  allied  forms  of  one  tvpe  of  structure. 

Localifi/  and  Strafi^raphical  Poniion. — This  Trchin  in  England  has  hitherto  been 
found  onlv  in  the  sands  and  gravels  near  Farringdon,  where  it  is  extremely  rare.  It  was 
collected  from  these  beds  by  the  late  Mr.  D.  Sharpe,  and  I  obtained  one  specimen  in  the 
same  locality.  On  the  continent  of  Europe  it  is  one  of  the  most  characteristic  fossils  of  the 
"Terrain  Xeocomien,"  and  is  found  principally  in  the  middle  beds  of  that  formation. 
'hi.  Cotteau  records  the  following  localities  in  France  where  it  has  been  collected : — Billecul, 
Mieges,  et  I'ermitage  de  Censeau,  Nozeroy  (Jura) ;  Morteau,  Hautepierre  (Doubs) ;  Ger- 
migney  (Haute-Saone) ;  Vassy,  Bettancourt,  (Haute-Marne'i ;  Thiefi'rain,  Vandoeu\Te, 
Marolles  (Aube) ;  Cheney,  Flogny,  Moneteau,  Auxerre,  Gy-rEveque,  Leugny,  Fontenoy, 
Saints,  Pereuse  (Yonne) ;  in  all  these  locahties  it  is  collected  in  abundance  from  the 
Ikliddle  Xeocomian  ;  and  at  Le  Rimet  (Isere),  Villefargeau,  Perrigny  (Yonne),  it  is  very 
rare  in  the  Upper  Neocomian.     In  Switzerland  it  is  found  near  Locle  in  the  Lower 

12 


90  PSEUDODIADEMA 

Neocomian ;  and  at  Laiuleron,  Saiiite-Croix,  Ilauterive  in  the  Middle  Neocomian,  so  that 
it  forms  a  leading  fossil  of  the  Neocomian  formations. 

History. — This  Urchin  was  at  first  referred  by  Professor  Forbes  to  the  Diadema  dubium 
of  Albin  Gras,  but  a  careful  comparison  of  specimens  proved  this  to  be  an  error.  It 
appeared  under  that  name  in  Mr.  Sharpe's  list  of  Echinodermata  from  the  sands  and 
gravels  of  Farringdon,  and  in  the  second  edition  of  the  '  Catalogue  of  British  Fossils.' 


PsEUDODiADEMA  FiTTONi,  Wright.     PI.  XV,  Figs.  1,  a — g. 

Diadema  Autissiodokense,  Wright.      Ann.  and  Mag.  of  Nat.  History,  New  Series, 

vol.  X,  p.  !)1,  1852. 

Test  pentagonal,  depressed  ;  inter-ambulacral  areas  with  two  rows  of  primary  tubercles 
and  two  incomplete  series  of  small  secondary  tubercles,  which  disappear  on  the  upper 
surface ;  ambulacral  areas  prominent,  with  two  rows  of  primary  tubercles  much  diminished 
in  size  at  the  upper  surface;  poriferous  zones  narrow,  subflexuous.  Pores  bigeminal 
near  the  ovarial  disc,  and  at  the  circumference  of  the  mouth. 

Dimensions. — Height  four  tenths  of  an  inch  ;  transverse  diameter  nineteen  twentieths 
of  an  inch. 

Description. — In  its  general  outline  this  beautiful  Urchin  resembles  P.  depressum  of 
the  Inferior  Oolite ;  in  the  details  of  structure,  however,  it  is  very  distinct  from  that  form. 
The  circumference  is  pentagonal,  from  the  convexity  of  the  ambulacral  areas,  and  the  upper 
and  under  surfaces  are  much  depressed  (PI.  XV,  fig.  1  a,  b,  c,  d). 

The  inter-ambulacral  areas  are  one  third  broader  than  the  ambulacral ;  two  rows  of 
primary  tubercles  occupy  the  centre  of  the  plates ;  there  are  about  ten  pairs  of  tubercles 
in  each  area,  which  are  of  a  moderate  magnitude,  and  gradually  diminish  in  size  from 
the  ambitus  to  the  base  and  summit ;  the  mammillary  eminences  are  small,  their  summits 
sharply  crenulated,  and  the  tubercles,  of  proportional  size,  are  deeply  perforated  (fig.  1  (/) ; 
at  the  ambitus  six  rows  of  granules  separate  the  tubercles  from  each  other  (fig.  1  e) ; 
towards  the  upper  part  of  the  mihary  zone  the  four  central  rows  are  absent,  leaving  a  naked 
space  in  the  middle  of  the  area  ;  three  rows  of  granules  in  like  manner  separate  the  tubercles 
from  the  poriferous  zones  ;  at  the  base  of  the  area,  and  extending  as  far  as  the  ambitus, 
there  are  incomplete  rows  of  small  secondary  tubercles  ;  these  gradually  diminish  in  size, 
and  disappear  at  the  upper  surface,  which  is  occupied  with  an  unequal  close-set  granulation 
about  three  rows  deep  (fig.  1  b) ;  the  ambulacral  areas,  one  third  narrower  than 
the  inter-ambulacral,  are  very  prominent  and  convex,  and  occupied  by  two  rows  of 
primary  tubercles  about  ten  in  a  row ;  the  lower  six  pairs  of  tubercles  are  nearly 
as  large  as  the  corresponding  tubercles  in  the  inter-ambulacral  areas,  but  the  upper 


FROM  THE  LOWER  GREENSAND.  91 

four  pairs  are  much  smaller,  so  that,  whilst  thei-e  is  a  great  uniformity  in  the  size  and 
form  of  the  tubercles  at  the  base  and  ambitus  of  the  test,  there  is  a  very  marked 
difference  between  those  of  the  ambulacra  and  inter-ambulacra  in  the  vicinity  of  the  apical 
disc  (fig.  1  b) ;  the  inter-tubercular  space  is  occupied  by  a  zigzag  band  of  granulation,  which 
is  narrow  below  where  the  tubercles  are  large,  and  broader  above  where  they  are  small 
(fig.  1  e).  The  poriferous  zones  are  narrow  and  subflexuous;  and  the  pores  arranged 
in  single  pairs ;  near  the  disc  they  are  slightly  bigeminal ;  the  apical  disc  is  absent  in  our 
specimen.     The  mouth-opening  is  large  and  the  peristome  slightly  decagonal  (fig.  1  c). 

Ajfinities  and  Differences. — Psciidodiadema  Fitloni  nearly  resembles  P.  Bour(/ueti,  Ag., 
but  diflers  from  it  in  the  rudimentary  condition  of  the  upper  tubercles  of  the  ambulacra, 
and  in  having  the  intermediate  granulation  on  the  miliary  zone  less  homogeneous. 

Locality  and  Slrafiffraphlcal  Position. — I  collected  this  Urchin  from  the  Lower  Green- 
sand  at  AtherficJd,  in  bed  No.  4  of  the  Cracker  group.  Dr.  Fitton's  section  ;  it  must  be  very 
rare,  as  none  of  the  cabinets  of  Atherfiekl  fossils  hitherto  examined  by  me  contain  a 
specimen. 

History. — I  discovered  this  fossil  in  IS 50,  and  in  the  first  instance  erroneously 
identified  it  with  a  specimen  found  in  France,  and  then  briefly  described  by  M.  Cotteau 
as  Diadema  Autissiodorense.  The  fine  figures  and  detailed  description  lately  published 
by  M.  Cotteau  in  his  additions  to  the  "  Paleontologie  Francaise  "  have  enabled  me  to 
correct  my  error,  and  I  now  dedicate  this  species  to  the  memory  of  my  late  friend 
Dr.  Fitton,  F.R.S.,  whose  admirable  memoir  on  the  Atherfiekl  section  and  the  strata  below 
the  Chalk  will  long  remain  models  of  patient  research  and  accurate  scientific  investigation. 


PsEUDODiADEMA  Malbosi,  Agassiz  8^'  Desor.     PI.  XX,  figs.  1,  a—f. 

Diadema  Malbosi,  Agassi:  and  Besor.  Catal.  r.iis.  des  Eehinides,  Ann.  Science. 

Nat.,  3me  ser.,  t.  vi,  p.  350,  184C. 

—  —  B'Orhignij.     Prodrome    de    Paleont.   strat.,    t.   ii,  p.    201, 

1850. 
DiPLOPOBiA  —  Desor.     Synops.  des  Eehinides  fossiles,  p.  7S,  pi.  xii,  figs. 

12—14,  1856. 
—  —  Leymerie   et    Cotteau.        Cafnl.    tics    Ecbinid.    Foss.     des 

Pyrenees,  Bullet.  Soc.  Geol.   dc  France,  2"  ser.,  t.  xiii, 

p.  324,  1850. 
DiAUEMA  Mackesoxi,  Forbes.      Woodward's   Notes   on  British   fossil  Diadems, 

IMem.  Geol.  Surv.,  Decade  V,  185G. 

—  Mackiei,  TJ'oodward.     Ibid. 

—  Malbosi,  Pictet.     Traite  de  Paleont.,  2"  ed.,  t.  iv,  p.  245,  1857. 
DirLOPODiA   —  I>'.//-c//«;c  Ics  Corbicrcs.   Mem.  Soc.  Geol.  de  France,  2"  ser., 

t.  vi,  p.  ;!84,  185!). 


02  PSEIDODIADEMA' 

DiPLOPoniA  ilAi.BOSi,  Bnjardin    et    Hiipe.      Hist.    Nat.      des    Zooph.    Ecbiuo- 

dermes,  p.  501,  18G2. 
PsEUDODivDEMA  ]\[.vLBosi,  Cotteou.     Ecliinid.  Foss.  des  Pyrenees,  p.  2G,  1863. 

—  —  Cotteau.     Paleontologie    Fran^aise,  Ter.    Crctace,  torn,  vii, 

p.  448,  pis.  1106  et  1107,  186."). 

Test  large,  subcircular,  upper  surface  convex,  slightly  inflated,  base  rounded  and 
flattened,  ambiilacral  areas  narrow,  contracted  at  the  upper  part  by  the  width  of  the  pori- 
ferous zones,  two  rows  of  tubercles  twenty  to  twenty-two  in  each  row.  Inter-ambulacral 
areas  wide  with  four,  six,  or  eight  rows  of  tubercles  at  the  equator,  the  two  inner  rows 
having  eighteen  to  twenty  tubercles  in  each,  extend  from  the  peristome  to  the  disc,  all 
the  others  disappear  at  different  points  on  the  sides.  Small  secondary  tubercles 
scattered  irregularly  among  the  primary  series  in  the  inferior  part  of  the  areas.  Poriferous 
zones  narrow  at  the  base  and  sides ;  pores  in  double  file  from  the  ambitus  to  the  disc, 
where  they  increase  in  width,  and  on  the  upper  third  are  largely  bigeminal.  Mouth - 
opening  moderate  in  size ;  peristome  nearly  equal  lobed ;  discal  opening  large  and 
acutely  pentagonal. 

Dimensions. — Transverse  diameter  two  inches  ;  height  thirteen  twentieths  of  an 
inch. 

Description. — ^This  is  a  very  rare  British  Urchin,  and  as  nearly  all  the  tests  have 
been  either  broken,  crushed,  or  otherwise  distorted,  it  is  difficult  to  form  a  correct 
idea  of  its  form.  I  have  carefully  examined  the  original  specimens  collected  by 
Mr.  Mackeson,  F.G.S.,  from  the  Lower  Greensand  at  Hythe,  and  presented  by  him  to 
the  Royal  School  of  Mines ;  these  I  have  compared  with  a  series  collected  by  my 
friend  the  Rev.  T.  Wiltshire,  from  the  Lower  Greensand  at  Whales'  Chine,  Isle 
of  Wight,  with  which  they  agree,  and  both  correspond  with  the  figures  and  descrip- 
tion of  Pseudodiadema  Malbosi  given  by  M.  Cotteau  in  the  '  Paleontologie  Franjaise,' 
and  with  a  good  type  specimen  kindly  presented  to  me  by  ]\L  Bayle,  of  the  Ecole 
des  ]\Iines,  Paris.  I  have  no  hesitation,  therefore,  in  considering  D.  Mackcsoni,  Forb., 
identical  with  D.  Malbosi,  Agass.  It  is  important  likewise  to  note  that  both  belong  to  the 
same  geological  horizon  ;  the  French  specimens  were  collected  from  the  Upper  Neoco- 
mian,  associated  with  EclMiospatagus  Collegnii,  Sisni.,  and  the  British  specimens  from 
the  Lower  Greensand  at  Ilythe,  and  the  Crioceras-beds,  Lower  Greensand,  at  Whales 
Chine,  Isle  of  Wight,  the  English  equivalent  of  the  Continental  Neocomian  formation. 

This  Urchin  attains  a  considerable  size  ;  Mr.  Wiltshire's  cabinet  contains  a  specimen 
measuring  two  and  a  half  inches  diameter.  The  base  of  this  fossil  is  nearly  circular,  and 
only  slightly  pentagonal.  In  some  of  the  Hythe  specimens  in  the  Museum  of  the  Royal 
School  of  Mines,  the  upper  surface  is  convex  and  moderately  inflated,  and  the  ba<e 
rounded  and  flattened. 

The  anibulacral  areas  are  narrow  and  contracted  at  their  apices  by  the  width  of  the 
poriferous  zones  above  Mig.  \,(j)\    they  are  slightly  inflated,  and  furnished  with  two 


FROM  THE  LOWER  GREENS  AND.  93 

rows  of  large  tubercles,  from  twenty  to  twenty-five  in  each,  according  to  the  size  of  the 
Urchin,  all  deeply  crenulated  and  perforated,  and  gradually  diminishing  from  the  equator 
to  the  apertures  ;  a  single  sinuous  line  of  granules  separates  the  tubercles,  which  are 
placed  closely  together  in  the  area  (fig.  1  d). 

The  poriferous  zones  are  narrow  at  the  base  and  sides,  where  the  pores  are  arranged  in 
a  single  file  (fig.  1  e);  at  the  upper  part  they  are  bigeminal  (fig.  1  cf),  the  double  rows 
encroaching  on  the  width  of  the  anibulacral  area  and  diminishing  the  size  of  the  tuber- 

cles  therein. 

The  poriferous  plates  are  prolonged  to  the  base  of  the  tubercles  in  more  or  less  apparent 

irregular  sutures  (fig.  1  d)- 

The  inter-ambulacral  areas  are  widely  developed,  the  large  plates  support  tubercles 
closely  resembling  those  of  the  ambulacra  (fig.  1  y).  In  the  figured  specimen  there  are 
six  rows  at  the  equator,  and  in  larger  specimens  there  are  eight  distinct  rows.  The 
two  internal  rows  have  eighteen  tul)ercles  a  little  larger  than  the  others,  extending 
from  the  peristome  to  the  disc  ;  the  other  rows  have  a  more  limited  range,  and  disappear 
on  the  upper  surface.  It  is  only  in  the  largest  specimens  that  eight  rows  are  found  at  the 
ambitus,  the  tubercles  of  the  shorter  rows  being  a  little  less  than  those  of  the  two  internal 
series  (fig.  1  y) ;  besides  the  primary  tubercles  a  number  of  small  secondary  tubercles 
are  crowded  along  each  side  of  the  median  suture,  between  the  peristome  and  the 
ambitus,  and  others  occupy  spaces  by  the  side  of  the  poriferous  zones.  The  miliary  zone 
is  wide,  smooth,  and  depressed  at  the  upper  surface ;  the  granules  are  irregularly  scattered 
on  its  lower  half,  and  some  of  them  are  even  developed  into  small  mammillated  tubercles 
on  the  npper  surface;  they  form  hexagonal  circlets  around  the  areas  of  the  primary 
tubercles  ;  the  median  suture  is  very  well  defined,  and  lies  in  a  smooth  depression  of  the 

test  (fig.  1  n,  c). 

The  mouth-opening  (fig.  1  d)  is  large  and  pentagonal,  and  the  peristome  divided  into 
lobes  of  unequal  sizes;  the  arches  that  span  the  ambulacra  are  longer  than  those  of  the 

inter-ambulacra. 

The  apical  disc  was  very  large ;  the  opening  is  pentagonal  and  acutely  angular,  the 
angles  extending  far  into  the  median  suture  of  the  inter-ambulacra  (fig.  1  a  andy). 

°The  spines" are  slender,  and  circular;  above  the  milled  ring  of  the  head,  there 
is  a  short  portion  of  the  stem  ornamented  with  fine  longitudinal  lines  (fig.  /), 
whilst  the  portion  beyond  is  entirely  smooth.     I  have  represented  this  character  in  the 

fragment  fig.  1  /• 

M.  Cotteau  has  figured  a  large  example  of  this  species  from  the  Upper  Ncocomian  ; 
from  this  we  learn  that  age  produces  important  modifications  in  the  structure  of  the  test ; 
the  poriferous  zones  arc  very  wide,  and  bigeminal,  not  only  on  the  upper  surface,  but  as 
far  down  as  the  ambitus  ;  besides  the  eight  rows  of  primary  tubercles  there  are  some 
rudiments  of  secondary  tubercles ;  the  miliary  zone  is  wide  and  depressed  at  the  upper 
surface;    the  discal  opening  becomes  more   angular,  and  the   ovarial  plates  penetrate 


94  PSEUDODIADEMA 

further  into  the  ambiilacral  areas  ;  the  mouth-opening  is  circular,  and  the  peristome  nearly 
equally  lobed. 

J/finities  and  Differences. — Pseudodiademu  ]\Ialbosi  resembles  some  of  the  larger  forms 
of  P.  Bronyniarii,  from  the  Grey  Chalk  of  Folkestone,  in  the  cabinet  of  my  friend  the 
Rev.  T.  Wiltshire,  and  figured  in  PI.  XX,  fig.  2  a,  h,  in  PL  XXI  b,  fig.  3,  and 
PL  XXI  A,  fig.  2.  The  tubercles  in  P.  Bronrjniarti  are  not  so  numerous  in  each  row; 
the  poriferous  zones  are  narrower,  and  the  bigeminal  arrangement  of  the  pores,  so  well 
developed  in  P.  Malbosi,  is  less  distinct  in  P.  Brongniarli.  These  certainly  are  nearly 
aUied  species,  and  require  a  careful  examination  to  detect  the  small  differences  existing 
between  them. 

p.  Malbosi  resembles  P.  dubium,  Gras,  from  the  same  horizon.  I  have  only  a  mould 
in  plaster  of  the  latter,  not  sufficiently  sharp  for  scientific  accuracy. 

Localitij  and  Stratigraphical  Position. — 'Lhe  specimens  I  have  figured  were  collected 
from  the  Lower  Greensand  at  Whales  Chine,  Isle  of  Wight,  in  the  Crioceras-beds  that 
pass  across  that  chasm,  associated  with  Ammonites  Martini,  D'Orb.,  Crioceras  Boioer- 
bankii.  Sow.,  Gryplicea  sinnata.  Sow.,  &c. 

The  specimens  in  the  Museum  of  the  Royal  School  of  Mines  were  collected  by  Mr. 
H.  B.  Mackeson,  from  the  Lower  Greensand  (Kentish  Rag)  of  Llythe,  and  presented  by 
him  to  that  institution.     Specimens  are  extremely  rare  in  both  the  places  cjuoted. 

The  foreign  /ocf//zY/r'.s,  according  to  jM.  Cotteau,  are  La  Classe  (Aude),  Opoul  (Pyrenees 
Orientales),  where  it  is  abundant  in  the  Upper  Ncocomian  beds,  associated  with  Echino- 
spatagws  CoUegnii,  D'Orlj. 


B. — Species  from  the  Gault. 
PsEUDor)iADEM.\  WiLTSHiREi,    Wright,  nov.  sp.     PL  XVI,  figs.  1  c— /,  2,  3. 

Test  moderately  large  and  equally  depressed  at  both  poles ;  ambulacral  areas  wide, 
with  two  rows  of  tubercles,  large  and  approximated  in  the  lower  half  of  the  area,  small  and 
detached  in  the  upper ;  poriferous  zones  narrow,  flexuous,  pores  in  single  file  throughout ; 
inter-ambulacral  areas  narrow,  two  roAvs  of  primary  tubercles,  and  a  few  irregular 
secondary  tubercles  at  the  base  of  the  area,  primaries  large  and  approximated  in  the 
lower  half,  small  and  remote  above;  miliary  zone  wide  and  finely  granulated  above, 
narrow  and  with  large  granules  below ;  spines  long  and  slender,  the  stem  ornamented 
with  delicate  longitudinal  lines. 

Dimensions. — Height  six  tenths  of  an  inch ;  transverse  diameter  an  inch  and  a  half. 

Description. — We  only  possess  a  fragment  of  this  beautifid  form,  still  it  has  been 
enough  to  enable  Mr.  Bone  to  give  a  restoration  of  the  test  in  PL  XVI,  fig.  1  b.  The  body 
is  inflated  at  the  sides,  and  nearly  equally  flattened  on  the  upper  and  lower  surface.     The 


FROM  THE  GAULT.  95 

ambulacral  areas  are  wide  and  have  two  rows  of  tubercles ;  those  on  the  lower  portion  of 
the  area  are  large  and  closely  set  together,  and  those  on  the  upper  part  are  dispropor- 
tionately small  and  placed  widely  apart  (fig.  1  b) ;  some  very  fine  granules  divide  the  large 
basal  tubercles,  and  a  numerous  granulation  surrounds  the  smaller  tubercles  on  the  upper 
part  (fig.  \  b). 

The  inter-ambulacral  areas  possess  only  two  rows  of  primary  tubercles ;  those  near  the 
base  are  about  the  same  size  as  the  corresponding  tubercles  in  the  ambulacra,  on  the  upper 
part  of  the  area,  they  are  larger,  and  diminish  more  gradually  in  size,  so  that  the 
difference  in  the  tubercles  on  the  upper  surface  readily  distinguishes  the  ambulacral  from 
the  inter-ambulacral  areas  ;  an  irregular  row  of  four  small  secondary  tubercles  occupies 
the  outer  side  of  the  base  between  the  primaries  and  the  poriferous  zones,  and  a  like 
central  row  extends  through  the  middle  of  the  lower  part  thereof  (fig.  1  c). 

The  miliary  zone  is  wide  and  depressed  in  the  upper  part,  and  the  plates  are  here 
covered  with  numerous  small  granules,  that  cluster  chiefly  around  the  bases  of  the  small 
tubercles,  the  median  sutural  space  being  depressed  and  nude  (fig.  1  b) ;  the  lower  part 
of  the  zone  is  narrow,  and  the  granules  are  much  larger  and  more  closely  set  together ; 
many  of  them  are  raised  on  small  mammillons,  with  secondary  tubercles  interspersed 
among  them  (fig.  1  c). 

The  large  primary  tubercles  of  both  areas  have  very  large  areolas  (fig.  1,  c),  with  well 
defined  margins.  Each  areola  consists  of  two  parts,  an  outer  circle,  consisting  of  a  band 
covered  with  microscopic  granules  (fig.  1  d),  and  a  smooth  inner  portion,  from  whence  the 
boss  arises  (fig.  1  e).  This  kind  of  ornamention  is  very  remarkable  ;  it  is  very  well  pre- 
served in  the  fragment  before  me,  and  correctly  represented  in  figs,  d  and  e.  The  summit 
of  the  boss  is  sharply  crenulated,  and  the  tubercle  deeply  perforated. 

The  spines  were  long  and  slender,  as  seen  by  some  imprints  on  the  slab  (figs.  I,  2,  3); 
the  acetabulum  of  the  small  head  is  marked  by  coarse  crenulations,  the  milled  ring  is 
prominent,  and  the  whole  surface  of  the  stem  covered  with  fine  longitudinal  lines. 

Affinities  and  Differences. — This  species  belongs  to  the  group  of  which  P.  Normanim 
(PI.  XXI,  fig.  3)  may  be  regarded  as  the  type.  It  differs  froni  that  species,  however,  in 
having  smaller  primary  tubercles  and  fewer  and  smaller  secondaries,  in  having  narroAver 
ambulacra  and  less  flexuous  poriferous  zones.  The  miliary  zone  is  likewise  less  distinctly 
marked ;  the  general  contour  of  the  test  is  different,  for  the  upper  and  lower  surfaces  are 
more  depressed  and  the  sides  less  inflated. 

Locality  and  StratigrapUcal  Position. — This  unique  specimen  was  found  by  the  Rev. 
T.  Wiltshire,  F.G.S.,  in  the  Gaalt  at  Folkestone,  in  a  bed  near  the  base  of  that  formation. 
I  have  very  great  pleasure  in  dedicating  this  species  to  my  kind  friend  as  an  acknow- 
ledgment of  the  important  assistance  he  has  rendered  me  during  the  progress  of  this 
work,  by  the  generous  contribution  of  all  his  best  specimens  for  figuring,  his  able  notes 
on  certain  species  of  Cidaris,  and  other  valuable  aid  frankly  given  on  all  occasions  when 
required. 


9G 


PSEUDODIADEMA 


c. — Species  from  the  Upper  Greensand. 


PsECUODiADEMA  RiioDANi,  Agassk.     PI.  XVIII,  figs.  3  a — c. 


DiADEMA  RhODAKI, 


Luc^, 
Rhodani, 


Rhodani, 

Luce, 

Rhodani, 

LUCE, 


Rhodani, 


PSEUDODIADEMA  LuCiE 


DiADEJtA  

—  \mcr, 

—  Desoki, 

pustulatum, 

Psecdodiadema  LuciE, 


Agassi:.     Cat.  Syst.  Ectyp.  foss.,  Mus.  Neoc,  Supplement, 

1840. 
Agassic.     Idem,  Mas.  Neoc,  p.  8. 
Agassi:.     Desc.   des  Echinid.  foss.  de  la  Suisse,  torn,  ii, 

p.  9,  pi.  xvi,  figs.  16—18,  1840. 
Agassi:.     Idem,  p.  8,  pi.  xvi,  figs.  11 — 15,  1840. 
Agassi:  and  Desor.     Cat.  Raison.  des  Echinld.,   Ann.   des 

Science  Nat.,  3'  sen,  t.  vi,  p.  346,  1846. 
Agassi:  and  Desor.     Idem. 
Bronn.     Inde.\  Palseontologicus,  p.  418,  1848. 
Bronn.     Idem,  p.  419. 

Albin  Gras.     Oursin.  foss.  de  I'lsere,  p.  33,  1848. 
IfOrhigmj.     Prodrome  de  Paleontol.  strat.,  t.  ii,  p.   142, 

Et.  19,  1850. 
Reiieriei:     Mem.   Geol.    sur  la   Perte  du   Rhone,    p.  49, 

1853. 
Morris.     Catalogue  of  British  Fossils,  2nd  ed.,  p.  70,  1854. 
McCoy.     Mesozoic  Radiata,  p.  67,  1854. 
Desor.     Synopsis  des  Echinides  fossilcs,  p.  "1,  1855. 
Rhodani,  Desor.     Idem,  p.  71. 

—        Picfef.     Traite  de  Paleontol..  2'-  ed.,  t.  iv,  p.  244,  1857. 
Picfef.     Idem. 
Forbes.     Notes  by  S.  P.  Woodward  ;  Memoirs  of  the  Geol. 

Surv.,  Decade  V,  p.  8,  1856. 
Forbes.     Idem,  p.  8,  1856. 
Dujurdin  et  Hupe.      Hist.  Nat.  des    Zoophytes,  Echino- 

dermes,  p.  498,  1862. 
Rhodani,  Dujardin  et  Hupi.     Idem. 
—  Cotteau.     Paleontol.  Francaise,  Terrain  Cretace,  p.  460, 

pi.  1110,  1864. 


Diapiosk. — Test  circular,  depressed,  slightly  convex  above,  very  concave  beneath, 
a  little  inflated  at  the  angles ;  ambulacral  areas  with  two  complete  rows  of  tubercles, 
fourteen  to  fifteen  in  each,  and  three  incomplete  rows  of  small  secondary  tubercles  at  the 
base,  five  or  six  in  each ;  inter-ambulacral  areas  with  two  rows  of  primary  tubercles,  thirteen 
or  fom'teen  in  each,  and  four  rows  of  small  unequal  secondary  tubercles  at  the  base; 
primary  tubercles  large  at  the  ambitus,  suddenly  diminishing  in  size  in  both  areas  on  the 


FROM  THE  UPPER  GREENSAND.  97 

upper  and  under  surface  ;  plates  covered  with  a  fine  uniform  granulation ;  moutli-opening 
situated  in  a  concave  depression. 

Dimensions. — Transverse  diameter  one  inch  and  one  tenth  of  an  inch,  height  half  an 
inch. 

Description. — Although  this  Diadema  exhibits  a  group  of  well-marked  specific  charac- 
ters, its  history,  nevertheless,  is  involved  in  much  confusion,  from  want  of  a  careful 
examination  of  the  anatomy  of  the  shell. 

The  prominent  ambital  tubercles  in  the  inter-ambulacra,  their  sudden  diminution 
in  size  on  the  upper  surface,  with  the  baldness  of  the  test  in  that  region,  and  the  crowding 
of  the  base  with  small  tubercles  nearly  uniform  in  size,  form  a  group  of  persistent 
characters  which  distinguish  Pseiidodiadema  Rhodani  from  all  its  congeners. 

The  smaller  forms  of  this  species  were  figured  and  described  by  Professor  Agassiz  as 
Diadema  Lucce,  and  the  large  tests  as  Diadema  Bhodani.  A  series  of  specimens,  of 
different  ages,  has  since  shown  that  these  two  forms  are  identical. 

This  initial  error  introduced  the  confusion  that  followed,  and  has  rendered  it  a  matter 
of  some  difficulty  to  understand  the  synonyms  of  this  species ;  the  careful  study  of  a 
good  type  form  sent  by  the  late  M.  Sgemann  from  the  Gault  (Etage  Albien,  d'Orbigny) 
of  Clars,  near  Escragnolle,  department  of  the  Var,  has  enabled  me  to  compare  our  English 
examples  with  an  undeniable  specimen,  and  from  this  examination  to  determine  'dwA.Diadema 
Desori,  Forb.,  and  D.  pustidatum,  Forb.,  are  different  forms  of  Pseiidodiadema  Rhodani. 
My  late  esteemed  colleague  Dr.  S.  P.  Woodward  adopted  Professor  Forbes's  materials  in 
his  "  Notes  on  British  Fossil  Diadems,"  contributed  to  Decade  V  of  the  '  Memoirs  of  the 
Geological  Survey ;'  and  it  is  evident  from  these  notes  that  he  had  his  doubts  as  to  the 
accuracy  of  our  lamented  friend's  determinations,  as  will  appear  in  the  description  of  the 
different  species. 

There  are  two  varieties  of  Pseudodiadema  Rhodani — a  large  form,  identical  with  the 
type,  figured  by  Agassiz,^  and  a  smaller  form,  corresponding  with  P.  Lucce.  The  former  I  have 
obtained  from  the  Chloritic  Marl  of  Chard ;  the  latter  from  the  Upper  Greensand  of 
Warminster,  where  it  appears  to  be  rare.  The  fine  example  figured  in  PI.  XVIII,  fig.  3, 
a,  h,  c,  is  of  moderate  size ;  the  test  is  circular  and  depressed,  slightly  convex  above,  in- 
flated at  the  sides,  and  very  concave  below ;  the  ambulacral  areas  are  large,  and  a  little 
expanded  at  the  sides  to  give  increased  space  to  the  ambital  tubercles ;  from  this  point 
they  taper  regularly  towards  both  poles.  There  are  two  rows  of  primary  tubercles,  from 
sixteen  to  seventeen  in  each,  extending  from  the  peristome  to  the  disc ;  three  of  these  in 
each  row,  at  the  ambitus,  are  large,  and  all  those  on  the  upper  surface  small,  dimi- 
nishing to  mere  granules  near  the  disc  (fig.  3  «);  the  tubercles  on  the  under  surface  are  small, 
and  have  a  uniform  size  to  the  peristome ;  in  this  region  the  area  is  filled  in  with  several 
smaller  secondary  tubercles  (fig.  3  b).     The  poriferous  zones  are  slightly  undidated  at  the 

1  'Description  des  Ecbinodermes  fossiles  de  la  Suisse,'  tab.  xvi,  figs.  16 — 18,  p.  9. 

13 


98  PSEUDODIADEMA 

sides  and  base ;  they  are  composed  of  simple  oval  pores  arranged  in  single  file  throughout 
(fig.  3  d).  The  inter-ambulacral  areas  one  half  wider  than  the  ambulacra!,  have  two  rows  of 
primary  tubercles,  fourteen  to  fifteen  in  each ;  a  little  larger  at  the  ambitus  and  upper 
surface  than  in  the  ambulacra ;  three  pairs  are  much  larger  at  the  sides,  those  on  the 
upper  surface  diminish  rapidly  in  size  between  the  ambitus  and  disc;  and  on  the 
under  surface  they  are  small  and  nearly  uniform  in  structure.  Between  the  basal 
angle  and  the  peristome  there  are  short  rows  of  secondary  tubercles,  about  the  size  of 
the  primaries  in  this  region,  with  a  few  scattered  secondaries  between  the  lateral 
rows ;  as  all  these  small  tubercles  are  nearly  the  same  size,  the  under  surface  of  the  test 
has  a  highly  ornamented  appearance — the  inter-ambulacra  with  four,  and  the  ambulacra 
with  two  rows  of  small,  uniform  tubercles,  and  several  secondary  ones  planted  at  every 
interval  on  the  plates  (fig.  3  3).  On  the  upper  surface  the  six  upper  tubercles  are 
small,  diminishing  to  mere  granules  around  the  discal  opening  (fig.  3  c).  The  large 
ambital  tubercles  are  smTounded  by  shallow  circular  areolas  (fig.  Sd).  In  some  specimens 
they  are  confluent,  in  others  separated  by  one  or  two  rows  of  minute  granules.  The 
small  dorsal  tubercles  are  surrounded  by  ring-like  areolas,  and  the  basal  tubercles  have 
a  chain-like  arrangement  of  granules  encircling  them,  which  adds  to  the  ornamentation  of 
this  region.  The  miliary  zone  is  very  large ;  from  the  sides  to  the  discal  aperture  the  entire 
surface  of  the  plates  of  both  areas,  except  those  portions  occupied  by  the  areolas,  is  covered 
with  small,  numerous,  close  set  of  granules,  which  form  divisional  partitions  on  each  side 
of  the  mesial  sutures  between  the  rows  of  the  primaiy  tubercles,  and  then  expand 
into  a  regular  corrugation  on  all  the  upper  surface,  the  dwarfing  of  the  tubercles  being 
compensated  by  an  increased  development  of  granular  ornamentation  on  this  region  of  the 
test.  The  base  is  very  concave,  and  the  small,  ch'cular  peristome,  indented  with  well- 
marked  entailles,  is  situated  at  the  bottom  of  a  deep  depression ;  the  entire  surface  of  the 
base  is  studded  with  small  tubercles,  surrounded  with  the  circles  of  granules  already 
described.  The  disc  is  absent  in  all  the  specimens  hitherto  found ;  the  opening  is  large 
and  pentagonal,  indicating  a  great  development  of  this  structure  in  the  species. 

Affinities  and  Differences. — P.  Hhodani  is  readily  distinguished  from  its  congeners  by 
the  subundulated  poriferous  zones,  small  dorsal,  intermediate  basal,  and  large  primary 
ambital  tubercles,  by  the  shortness  of  the  secondary  rows  limited  to  the  base,  by  the 
smallness  of  the  dorsal  tubercles  and  the  fine  homogeneous  granulation  on  the  miliary 
zone ;  the  concavity  of  the  base,  smallness  of  the  peristome,  and  depth  at  which  it  lies, 
added  to  the  highly  ornamented  character  of  the  plates,  form  a  group  of  characters 
that  readily  distinguish  it  from  all  others.  It  resembles  most  P.  Normanics  (PI.  XXI, 
fig.  3),  from  the  Grey  Chalk  of  Folkestone,  in  the  varied  development  of  the  tubercles 
in  each  row  ;  the  ensemble  of  the  test  in  the  latter  form  is  sufficiently  defined  by 
good  specific  characters,  and  for  the  definition  of  these  I  must  refer  to  the  article 
on  that  species. 

Locality  and  Strati (/rapldcal  Position. — The  large  example  I  have  figured  was  found 


FROM  THE   UPPER  GREENSAND.  99 

in  the  Chloritic  Marl,  fall  of  green  specks  of  iron,  at  Chard,  associated  with  Catopygus 
carinatus,  Goldf.,  Biscoidea  subuculus,  Leske,  Pseudodiadema  ornatum,  Goldf.,  P. 
variolare,  Brong.,  with  Ammonites  splendens.  Sow.,  A.  varians,  Sow.,  and  other  forms 
characteristic  of  the  Upper  Greensand  formation.  The  specimens  from  Warminster,  in 
the  Museum  of  the  Royal  School  of  Mines,  and  in  the  Collections  of  Mr.  Soper  and  Mr. 
Cunnington,  Devizes,  were  found  in  the  Upper  Greensand  with  P.  Michelini,  Agas.,  and 
P.  Benefliw,  Forb.,  and  other  common  Upper  Greensand  forms,  as  Catopygiis  curinatus, 
Goldf.,  Salenia petalifera,  Agass.,  and  Goniopyt/us peltatus,  Agas.,  &c.  &c. 

Foreign  Distribution. — Geraudot  (Aube)  ;  Perte  du  Rhone  (Ain) ;  Clars,  Escragnolle 
(Var) ;  very  common  in  the  Etage  Albien  (Cotteau). 

History. — First  figured  by  Professor  Agassiz  in  1840,  the  large  forms  as  Diadema 
Bhodani,  the  smaller  as  D.  Luccb.  After  much  confusion  it  was  discovered  that  these 
forms  are  identical.  Professor  Forbes,  from  not  possessing  types  of  Pseudodiadema 
Bhodani,  named  the  large  form  Diadema  pustulatum,  and  the  small  ones  from  War- 
minster D.  Desori ;  this  nomenclature  was  adopted  by  Dr.  S.  P.  Woodward,  in  1856,  in  his 
"  Additional  Notes  on  British  Fossil  Diadems,"  published  in  Decade  V  of  the  '  Memoirs 
of  the  Geological  Survey.'  M.  Cotteau,  in  1863,  has  given  admirable  figures,  and  a 
most  correct  description  of  the  species,  which  my  observations  confirm  in  all  their  details. 


Pseudodiadema  Michelini,  Agassiz.     PI.  XIX,  figs.  .2,  a — -f. 

Diadema  Micheltni,  Agassiz.   Catal.Syst.  Ectyp.  foss.  Mus.  Neoc,  p.  8, 1840. 

__  Agassis  et  Desor.      Catal.  rais.    des  fichinides,  Ann. 

Sc.  Naturelles,  3"  ser.,  t.  vi,  p.  347,  1846. 

—  —  Bronn.     Index  Palscont.,  p.  418,  1848. 

—  —  Sorignet.     Ours.  foss.  de  dep  de  I'Eure,  p.  25,  1850. 

—  —  B'Orbigwj.     Prod.  Paleont.  strat.,  t.  ii,  p.  179,  1850. 

—  BoNEi,   '  Fories.  In  Morris's  Catalogue  of  British  Fossils,  2nd  ed., 

p.  7C,  1854. 

—  —  O'^oorfwarrf.  Mem.  of  Geo).  Survey,  Decade  V.explan.  of 

pl.ii,  1856. 
Pseudodiadema  Michelini,     Desor.     Synopsis  des  iScliinides  fossiles,  p.  72,  185G. 
Diadema  Michelini,  Pictet.     Traite  de  Paleont.,  2'  ed.,  t.  iv,  p.  245,  1857. 

Pseudodiadema  pulchellum,  Cotteau.     Echinides  nouv.  ou  peu  connus  (Revue  de 

Zoologie),  p.  3,  pi.  i,  fig.  7—9,  1857. 
Pseudodiadema  Michelini,    Bujardin  et  Hup£.     Hist.  Nat.  des  Zoophytes,  Echino- 

derm.,  p.  499,  1862. 
—  Cotteau.  Paleontologie  Fran^aise,  Terrain Cre'tncc,  p.  476, 

pi.  1114,  1864. 

Diagnosis.— Test  circular,  or  slightly  pentagonal,  depressed ;  base  flat,  inflated  at  the 
margin,  concave  towards  the   mouth ;  ambulacral   areas  large,  two  rows  of  prominent 


100  PSEUDODIADEMA 

primary  tubercles,  12^14  in  each  row;  interambulacral  areas  with  two  rows  of  primary 
tubercles,  12 — 14  in  a  row,  and  two  external  rows  of  small  secondary  tubercles,  extend- 
ing from  the  peristome  to  the  ambitus ;  mouth-opening  small,  in  a  concave  depression ; 
tubercles  of  both  areas  nearly  the  same  size. 

Dimensions. — Height   six  tenths  of  an  inch ;  transverse  diameter  one  inch  and  one 
fifth. 

Description. — This  Urchin  is  in  general  of  medium  size,  with  a  sub-circular  or  pen- 
tagonal test,  convex  above  and  flat  below  ;  the  ambulacral  areas  are  large,  slightly  inflated, 
and  provided  with  two  rows  of  small  primary  tubercles,  12 — 14  in  a  row,  rather  less  than 
those  in  the  interambulacral  areas,  and  separated  by  a  double  zigzag  row  of  very  small 
granules  (fig.  2  d),  gradually  diminishing  in  size  from  the  ambitus  to  both  poles ;  the 
poriferous  zones  are  subflexous  and  composed  of  pairs  of  small  round  holes  placed  in  single 
file  throughout,  crowded  together  near  the  peristome,  and  spread  out  above ;  the  inter-ambu- 
lacral  areas  are  twice  the  width  of  the  ambulacral  and  furnished  with  two  rows  of  primary 
tubercles  rather  larger  than  those  of  the  ambulacral  areas  ;  they  ;ire  very  uniform  in  size 
and  gradually  diminish  from  the  ambitus  to  the  poles ;  between  these  rows  and  the 
poriferous  zones,  and  between  the  two  rows  themselves,  a  series  of  small  tubercles,  6 — 8 
in  number,  extends  fi'om  the  peristome  to  the  ambitus,  where  they  disappear ;  these  small 
secondary  tubercles  fill  up  the  intertubercular  spaces  at  the  base,  and  give  the  under  sur- 
face of  the  test  a  very  ornamental  appearance  (fig.  2  b).  There  are  fourteen  plates  in  each 
column  of  the  inter-ambulacra,  the  primary  tubei'cle  occupying  the  centre  of  each  ;  the 
areolas  are  circular  and  superficial,  the  bosses  prominent  and  sharply  crenulated,  and  the 
mammillons  large  and  deeply  perforated  (fig.  2  d) ;  the  surface  of  the  plates  is 
sparsely  covered  with  small  granules  which  form  circles  around  the  areolas  and  are 
scattered  without  order  over  the  interspaces ;  the  internal  borders  of  the  four  upper- 
most plates  of  both  columns  are  nude  (fig.  2  b) ;  and  the  sutures  distinctly  visible 
throughout  their  entire  course.  The  ambulacral  areas  have  fourteen  plates  in  each  column, 
the  tubercles  are  rather  smaller  than  those  in  the  inter-ambulacra,  and  the  narrow  areolas 
are  separated  by  a  zigzag  line  of  single  granules  (fig.  2/),  which  becomes  double 
(fig.  2  d)  near  the  ambitus.  The  miliary  zone  is  large,  nude,  and  depressed  at  the  upper 
part,  granular  towards  the  equator,  and  narrow  and  sinuous  as  it  approaches  the  peristome 
(fig.  2  c). 

The  mouth-opening  is  small,  and  lodged  in  a  deep  depression,  the  basal  portion  of 
the  test  being  inflated  around  the  peristome,  which  is  decagonal,  with  nearly  equal 
lobes  (fig.  2  5). 

The  apical  disc  is  absent  in  all  the  specimens  I  have  examined ;  the  opening,  however, 
is  large,  a  little  elongated,  subpentagonal,  and  angular  (fig.  2  a). 

Jffinifics  and  Differences. — This  Urchin  is  distinguished  from  its  congeners  by  its  in- 
flated base, depressed  upper  surface,  simple  pores,numerous  primary  tubercles  nearly  uniform 
in  size  and  number  in  the  columns  of  both  areas,  by  its  small  unequal  secondary  tubercles. 


FROM  THE  UPPER  GREENSAND.         •  101 

extending  at  the  base  between  the  primaries  and  the  poriferous  zones,  and  by  its  narrow 
peristome  sunk  in  a  deep  depression ;  a  careful  comparison  of  typical  specimens  of  Diadema 
Michelini,  Ag.,  from  the  Upper  Greensand  of  Villers-sur-Mer,  Calvados,  kindly  sent  by 
M.  Michelin,  has  satisfied  me  that  Diadema  Bond,  Eorb.,  is  identical  with  D.  Michelini; 
and  that  P.  Benettice,  Eorb.  (PI.  XV,  fig.  2),  both  as  regards  its  general  form,  the  number, 
disposition,  and  character  of  its  primary  and  secondary  tubercles,  the  sraallness  of  the 
mouth-opening,  situated  in  a  deep  depression,  and  the  equal  lobes  of  the  peristome,  is 
identical  with  some  forms  of  P.  Michelini  oi\\\^  same  size. 

Locality  and  Straii graphical  Position. — This  species  is  very  common  in  the  Upper 
Greensand  near  Warminster ;  the  smaller  forms  arc  very  closely  allied  to  the  Diadema 
BenetticB,  Forb.,  the  larger  to  the  D.  Bonei,  Eorb. ;  it  has  likewise  been  found  in  the  same 
formation  at  Durdle  Cove,  Dorset. 

Foreign  Localities. — It  has  been  collected  from  the  Etage  Ccnomanien  of  France  (  = 
Upper  Greensand)  at  Villers-sur-Mer,  Cauville,  Vaches-Noires,  Saint-Jouin  (Calvados) ; 
Octeville  (Manche) ;  Fecamp,  Orcher,  Le  Havre,  Rouen  (Mont-St.-Catherine),  Seine-Infer. ; 
Vimoatiers,  Grace  (Orne) ;  Prcsagny  (Eure). 


PsEUDODiADEMA  Benetti^,  Forbcs.     PL  XV,  figs.  2,  a—f. 

Diadema  Benetti.e,  Forbes.     Morris,  Cat.  Brit.  Foss.,  2nd  cd.,  p.  7C,  1854. 

—  —  Woodvjard.     Memoirs  of  tlie  Gcol.  Siirv.,  Decade  V,  p.  7, 

1856. 
PsECDODiADEMA  Benetti.s,  Besor.     Synopsis  des  Echinides  fossiles,  p.  72,  1858. 

—  —  Bvjardin  et  Hvpi.      Hist.  Nat.  des  Zoophytes,   EcLino- 

dermes,  p.  499,  18G2. 

—  Michelini,  Colteau  (pars).     Paleontologie  Fran9aise,  Terrain  Cretace, 

p.  476,  1864. 

Test  circular,  inflated,  depressed;  ambulacral  areas  wide,  with  two  rows  of  tubercles 
15  in  each,  separated  by  a  double  row  of  minute  granides;  inter-ambulacral  areas  with 
two  rows  of  primary  tubercles,  14  in  each;  separated  by  a  wide  median  space,  unequally 
granulated ;  miliary  zone  smooth  above ;  a  few  small  secondary  tubercles  at  the  base ; 
primary  tubercles  of  both  areas  nearly  of  the  same  size.  Peristome  very  small,  deeply 
sunk  in  a  concave  depression  ;  discal  aperture  large  and  pentagonal. 

Dimensions. — Transverse  diameter  one  inch ;  height  four  tenths  of  an  inch. 

Description. — This  beautiful  little  Urchin  was  formerly  considered  to  be  the  Diadema 
ornatum,  Goldf.,  and  recorded  as  such  in  the  first  edition  of  jMorris's  '  Catalogue  of 
British  Fossils.'  It  was  subsequently  considered  by  Professor  Forbes  to  be  a  distinct 
species,  and  in  the  second  edition  of  that  work  was  dedicated  by  him  to  the  late  Miss 


102  PSEUDODIADEMA 

E.  Benett,  of  Norton  House,*  Wilts.  It  was  first  accurately  described  by  the  late  Dr. 
Woodward  in  his  Notes  on  Fossil  Diadems. 

The  test  is  circular,  depressed  on  the  upper  surface,  concave  below,  and  inflated  at  the 
sides.  The  ambulacral  areas  are  proportionally  wide,  with  two  rows  of  tubercles  separated 
by  a  double  row  of  granules  ;  there  are  from  12 — 15  in  each  row,  according  to  age ;  they  in- 
crease gradually  in  size,  from  the  peristome  and  disc  towards  the  ambitus,  where  they  are 
largest;  the  poriferous  zones  are  narrow  and  slightly  undulated;  the  pores  are  in  oblique  single" 
file  throughout,  three  pairs  of  holes  being  opposite  each  ambulacral  plate  (fig.  2  a),  where 
they  are  magnified  four  diameters ;  the  pores  at  the  circumference  have  a  small  tubercle 
between  each  pair ;  the  inter-ambulacral  areas  are  about  one  fourth  part  wider  than  the 
ambulacral;  they  have  two  rows  of  tubercles,  from  12 — 14  in  each,  separated  by  a  wide 
miliary  zone,  which  is  unequally  granulated,  and  becomes  smooth  on  the  upper  surface ; 
a  similar  sparsely  granulated  space  separates  the  tubercles  from  the  poriferous  zones ; 
and  at  the  base  of  the  area  a  short  row  of  small  secondaiy  tubercles  extends  from 
the  peristome  to  the  angle,  between  the  large  tubercles  and  the  poriferous  zones.  The 
tubercles  of  both  areas  are  nearly  of  the  same  size,  those  of  the  inter-ambulacral  are 
the  largest;  they  have  all  distinct  oval  areolas,  which  are  sometimes  radiated,  and 
encircled  by  rows  of  very  small  granules.  The  base  is  inflated  at  the  circumference, 
and  concave  in  the  middle  ;  the  peristome  is  small  and  deeply  sunk,  about  one  third  the 
diameter  of  the  test ;  its  margin  is  divided  by  feeble  entailles.  The  disc  is  absent  in  all 
our  specimens ;  the  aperture  is  wide  and  pentagonal,  the  angles  pointing  towards  the 
median  suture  of  the  inter-ambulacral  areas. 

JMnilies  and  Differences. — This  species  so  much  resembles  Pseudodiadema  Michelini, 
A"-.,  that  it  has  been  considered  by  some  authors  to  be  the  same.  M.  Cotteau  says,  "  P. 
Michelini,  such  as  we  understand  it,  cannot  be  distinguished  from  P.  Benettice,  Eorb.,  and 
we  do  not  hesitate  to  unite  the  two  species,  which  present  in  their  form,  in  the  disposition 
of  their  tubercles,  in  the  structure  of  their  peristome,  in  a  word,  in  the  ensemble  of  their 
characters,  an  identity  almost  complete."  Admitting,  as  I  do,  the  great  similarity  of  the 
tests  of  the  two  forms,  still  I  think,  by  a  careful  study  of  both,  we  can  detect  characters 
which  may  justify  us  in  retaining  our  lamented  colleague's  species.  P.  Benett ia  has  the 
tubercles  smaller,  the  sides  more  inflated,  the  circumference  of  the  base  more  convex,  and 
the  mouth-opening  smaller  and  lodged  in  a  deeper  depression.  P.  Michelini  is  a  flatter 
Urchin  and  the  size  and  greater  prominence  of  the  tubercles  impart  to  it  a  more  spinous 
character ;  if  these  points  of  diS"ercnce  in  the  test  are  borne  out  by  any  corresponding 
difi"erence  in  the  spines,  the  species  may  be  sustained ;  if  not,  P.  Bennetice  may  turn  out  to 
be  a  mere  variety  of  P.  Michelini. 

Locality  and  Stratigraphical  Position. — This  is  a  very  abundant  species  in  the 
junction-beds   of  the   Upper  Greensand  at  Warminster,  associated  with    P.  Michelini, 

'  Authoress  of  '  A  Catalogue  of  WiltsLirc  Fossils,'  1831. 


FROM  THE  GREY  CHALK.  103 

Catopygus  carinatus,  and  the  other  species  of  this  zone.     It  has  been  collected  from  the 
same  beds  at  Durdle  Cove,  on  the  Coast  of  Dorset. 

Foreign  Distribution. — M.  Desor  states  that  F.  Benettice  is  found  in  the  Craie 
chloritee  (Cenomanien)  of  Villers-sur-Mer,  Vaches-noires,  de  Gace,  Orne,  and  is  common 
in  all  French  collections. 


D.  Species  from  the  Grey  Chalk. 

PSEUDODIADEMA   ORNATUM,   Goldf.,  Sp.       PI.  XVI,  figS.  4  a 6;    PI.  XIX,  flgS.  1  a — C ;   PI. 

XXI,  figs.  1  a—d,  2;  PI.  XXI  a,  figs.  1  a,  h. 

CiDAEiTES  OKNATUS,  Gold/uss.     Petref.  GerraauiiB,  tab.xl,  fig.  10,  p.  123,  1826. 

DiADEMA  OKNATUM,  Agassiz.     Prod,   d'une  Monogr.  des  Radiares,  Mem.  Soc. 

des  Sc.  Nat.  de  Neufchatel,  t.  i,  p.  118,  1836. 

—  —  BesmouUns.    Etudes  sur  les  Echinides,  p.  314,  No.  15,  1837. 

—  —  Dujardin.     InLamarck'sAnim.  sans  Vertebras,  2°  ed.,  t.  iii, 

p.  392,  1840. 

—  —  Roemer.     Norddeutschen  Kreidegebirges,  p.  29,  1840. 

—  —  Agassiz  et  Desor.     Catalogue  raison.  des  Echinides,  Ann. 

Sc.  Nat.,  2'  ser.,  t.  vi,  p.  347,  1846. 

—  —  Brorm.     Index  Palaeont.,  p.  449,  1848. 

—  —  jyOrbigny.      Prod,  de  Paleont.  strat.,  t.  ii,  p.  169,  fit.  20, 

No.  560,  1850. 

—  —  Forbes.     In  Morris's  British  Fossils,  2nd  ed.,  p.  77,  1854. 

—  —  McCoy.     Contributions  to  Brit.  Palseontology,  p.  67,  1854. 

—  —  Desor.     Synopsis  des  Ecbinides  fossiles,  p.  72,  1856. 

—  —  Woodward.     Mem.  of  Geol.  Surv.,  Decade  V,  p.  7,  1856. 

—  TUMIDUM,  Woodward.     Mem.  Geol.  Surv.,  Decade  V,  1856. 

—  CAETERI,  Woodward.     Ibid. 

PsEUDODiADEMA  ORH ATm\,  Pictet.     Traite  de  Paleontol.,  2'  ed.,  t.  iv,  p.  245,  1857. 

—  —  Dujardin  et  Hupe.     Hist.  Nat.  des  Zoophytes,  Echinod., 

p.  499,  1862. 

—  —  Cotteau.    Paleontologie  Frangaise,  Terrain  Cretace,  pi.  1115, 

tom.  ii,  p.  480,  1864. 

Test  circular,  inflated ;  ambulacral  areas  straight ;  tubercles  small,  numerous,  sub- 
equal,  in  two  rows,  separated  by  a  double  series  of  granules;  inter-ambulacral  areas 
with  two  rows  of  tubercles,  separated  by  four  rows  of  granules  at  the  ambitus,  which 
disappear  at  the  upper  surface,  and  leave  a  smooth  depressed  space  in  the  middle  of  the 
miliary  zone,  bordered  by  two  rows  of  granules;  between  the  tubercles  and  poriferous 
zones  a  row  of  secondary  tubercles  extends  from  the  peristome  to  near  the  disc,  consisting 
of  small  well-spaced-out  tubercles,  each  surrounded  by  a  circle  of  granules.  Areolas  cir- 
cular, many  of  them  radiated ;  tubercles  of  both  areas  nearly  equal  in  size. 

Dimensions. — Height  half  an  inch ;  transverse  diameter  one  inch  and  two  tenths. 


104  PSEUDODIADEMA 

Descri])tion. — This  beautiful  Urchin  when  full  grown  is  moderately  large ;  it  has  a 
circular,  elevated,  and  inflated  form,  depressed  on  the  upper  surface,  and  concave  beneath. 

The  ambulacral  areas  are  large,  a  little  inflated,  and  furnished  with  two  rows''of 
moderately  sized  tubercles,  14 — 16  in  a  row;  one  of  these  is  always  longer  than  the 
other,  and  separated  from  its  fellow  by  a  double  series  of  small  compact  granules.  The 
poriferous  zones  are  straight  and  narrow  at  the  base  of  the  test,  and  gently  subun- 
dulated  from  the  ambitus  to  the  apical  disc ;  they  are  composed  of  simple  pores  closely 
approximated  to  each  other ;  the  pairs  are  well  spaced  out  in  the  infra-marginal  region, 
closer  together  at  the  equator,  and  still  closer  placed  near  the  disc.     PI.  XXI,  figs.  1  b,  c. 

The  inter-ambulacral  areas  are  large,  and  provided  with  two  rows  of  tubercles,  nearly 
identical  in  size  with  those  of  the  ambulacral  areas  at  the  base  and  ambitus  of  the 
same  regions ;  in  the  upper  part  of  the  area,  however,  they  are  proportionally  larger, 
so  that  we  find  only  13 — 15  tubercles  in  each  row.  The  secondary  tubercles  form  a 
distinct  series  of  from  seven  to  nine  small  tubercles,  situated  between  the  primary  row 
and  the  poriferous  zones ;  in  general  one  small  tubercle  arises  from  each  plate  between 
the  peristome  and  ambitus  (PI.  XIX,  fig.  1  (/),  and  is  absent  from  the  three  or  four  upper 
plates  of  the  test  (PI.  XVI,  fig.  4  e) ;  besides  these,  there  are  other  smaller  tubercles,  of 
unequal  size,  scattered  between  the  primary  and  secondary  rows  (PI.  XIX,  figs.  1  b,  c,  d). 

The  miliary  zone  is  very  wide;  it  is  narrow  near  the  peristome,  enlarged  at  the 
ambitus,  and  nude  and  depressed  on  the  upper  surface  (PI.  XVI,  figs.  4  c  and  e).  The 
granules  are  numerous,  unequal,  sometimes  mammillated,  and  distinguished  with  difficulty 
from  the  small  secondary  tubercles  among  which  they  are  interspersed  (PI.  XXI,  figs.  \  a,c; 
PI.  XVI,  figs.  4  c,  ^). 

The  primary  tubercles  of  both  areas  have  well-defined  circular  areolas,  prominent 
bosses,  with  sharply  crenulated  summits,  and  large  mammillons  with  deeply  drilled  summits ; 
the  inter-ambulacral  are  a  little  larger  than  those  of  the  ambulacral  areas.  The  areolas  near 
the  ambitus  are  mostly  confluent  above  and  below,  whilst  on  the  upper  surface  of  the  inter- 
ambulacra  they  are  distinct,  and  surrounded  by  circles  of  small  granules  (PL  XXI,  fig.  1  c). 

The  under  surface  is  convex  at  the  circumference,  with  a  deep  depression  in  the 
middle,  in  which  the  mouth-opening  is  situated.  The  peristome  is  very  small,  and  its 
margin  feebly  indented.  The  discal  opening  is  large,  elongated,  and  sub-pentagonal. 
Unfortunately,  all  the  specimens  hitherto  found  want  the  discal  plates  (PI.  XIX,  fig.  1  b). 

Affinities  and  Differences. — This  Urchin  resembles  P.  Michel i iii ;  it  is,  however,  distin- 
guished from  that  species  by  its  much  greater  height,  inflated  sides,  narrow  base, 
slightly  undulated  poriferous  zones,  more  numerous  and  better  developed  secondary 
tubercles,  more  deeply  sunk  peristome,  and  elongated  discal  opening;  these  diagnostic 
characters  are  not  the  result  of  age,  as  they  are  observed  more  or  less  in  comparing 
young  specimens  of  both  species  apparently  of  the  same  age  with  each  other. 

Localifi/   and  Stratigraphical  Position. — The    specimens    figured,   from   the   Grey 
Chalk,  Folkestone,  on  Pis.  XVI,  XIX,  and  XXI  a,  belong  to  the  Rev.  T.  Wiltshire,  the 


FROM  THE  GREY  CHALK.  105 

British  Museum,  and  my  cabinet.  I  have  examined  a  specimen  from  the  Red  Chalk  of 
Hunstanton  Cliff,  belonging  to  my  friend  C.  B.  Rose,  Esq.,  F.G.S.,  who  has  most  kindly 
communicated  many  of  his  Echinodermata  for  this  work.  The  specimen  figured  in 
PI.  XXI,  fig.  1,  now  in  my  cabinet,  was  collected  from  the  remarkable  bed  of  Chloritic 
Marl  at  Chard,  which  has  yielded  so  many  fine  examples  of  Echinidce.  The  specimen  in 
the  Cambridge  Museum  is  recorded  by  Professor  McCoy  as  having  been  collected  from 
the  Upper  Greensand  of  Blackdown.  Many  of  the  specimens  sent  me  as  P.  Carteri 
by  my  friend  Mr.  J.  Walker,  F.G.S.,  and  collected  by  him  from  the  copvolite  beds  of  the 
Upper  Greensand  near  Cambridge,  are  undeniable  specimens  of  P.  ornahun. 

Foreign  Distribution. — Frcmce. — Rouen,  Mountain  of  St.  Catherine,  Seine-Inferieure  ; 
Vimoutiers  (Orne),  in  the  Btage  Ccnomanien,  where  it  is  rare.  Germany. — Essen-on-the- 
Ruhr,  Westphalia,  whence  Goldfuss's  type  specimen  was  obtained. 

Histori/. — This  Urchin  was  first  figm'ed  and  described  in  the  '  Petrefacta  Germanise'  by 
Goldfuss,  in  1826,  under  the  name  Cidarites  ornatus.  Professor  Agassiz,  in  1836, 
erroneously  referred  to  this  species  a  small  Neocomian  form,  which  was  subsequently 
separated  under  the  name  Diadema  Bouryueti.  In  the  first  edition  of  the  '  Catalogue  of 
British  Fossils,'  Diadema  Benettice  was  recorded  as  D.  ornatum  on  the  authority  of 
Dr.  Woodward.  Professor  Forbes  named  the  tumid  varieties  of  this  Urchin  Diadema 
tumidum,  and  under  this  name  they  are  described,  from  type  specimens,  in  my  cabinet 
(PI.  XXI,  fig.  1),  by  Dr.  S.  P.  Woodward,  in  his  "  Notes  on  British  Fossil  Diadems,"  con- 
tributed to  Decade  V,  '  Memoirs  of  the  Geological  Survey.' 


PSEUDODIADEMA  NoRMANIiE,  Cotteaii,  18C3.     PI.  XXI,  fig.  3,  a,  d. 

PsEUDODiADEMA  NoRMANiyE,  Cotteau.     Paleontologie  rran9aise.  Terrain  Cretace,  t.  vii, 

p.  4G8,  pi.  1112. 

Test  of  moderate  size,  subcircular,  inflated  at  the  sides,  and  convex  above ;  base  rounded 
at  the  margin,  and  very  concave  in  the  centre ;  ambulacral  areas  wide,  with  two  rows  of 
tubercles,  large  at  the  ambitus  and  small  on  the  upper  and  infra-marginal  regions,  sepa- 
rated by  several  rows  of  minute  unequal  granules ;  inter-ambulacral  areas  narrow,  with 
two  rows  of  primary  tubercles,  nearly  similar  in  size  and  development  to  those  of  the 
ambulacra,  and  numerous  small,  unequal,  secondary  tubercles,  forming  in  the  infra-mar- 
ginal region  six  short  series,  two  on  each  side,  and  two  in  the  middle  of  the  primary 
rows  ;  mouth-opening  lodged  in  a  deep  depression. 

Dimensions. — Height  six  tenths  of  an  inch ;  transverse  diameter  one  inch  and  four  tenths. 

Description. — This  rare  and  beautiful  Urchin  is  of  medium  size ;  it  has  a  subcircular 
form,  with  broad  inflated  sides,  convex  at  the  upper  surface  and  very  concave  beneath.  The 
ambulacral  areas  are  wide  in  the  middle,  lanceolate  in  the  upper  part,  and  narrow  in  the 
infra-marginal  region  ;  they  have  two  rows  of  primary  tubercles,  of  which  two  pairs  at  the 

14 


lOG  PSEUDODIADEMA 

ambitus  are  very  largely  developed,  and  occupy  the  greatest  part  of  the  area,  having  large 
areolas,  prominent  bosses,  sharply  crenulated  summits,  with  projecting,  deeply  perforated 
mammillons  (PI.  XXI,  fig  3  d) ;  on  the  upper  surface  they  rapidly  diminish  in  size  ;  four  of 
them  have  small  areolas  and  the  others  become  mere  granules.  In  the  infra-marginal  region 
they  gradually  diminish  as  they  approach  the  peristome,  where  two  short  rows  of  secondary 
tubercles  are  regularly  arranged.  The  primary  tubercles  are  separated  by  two  rows  of  very 
fine  granules,  which  gradually  increase  in  number,  and  fill  the  entire  upper  portion  of  the 
area  (fig.  3  d). 

The  poriferous  zones  are  narrow  and  straight  at  the  base,  undulated  on  the  sides,  and 
straight  again  on  the  upper  surface ;  the  pores  are  simple,  round,  largely  open,  and 
arranged  in  a  single  file  throughout  (fig.  3  c  and  d). 

The  inter-ambulacral  areas  are  relatively  small  from  the  excessive  width  of  the  ambu- 
lacra ;  they  have  two  rows  of  primary  tubercles,  of  which  three  pairs  at  the  ambitus,  like 
those  in  the  ambulacral  areas,  attain  a  great  development ;  above  they  become  suddenly 
smaller,  and  diminish  to  mere  granules ;  and  on  the  infra-marginal  region  they  become 
gradually  smaller  as  they  approach  the  peristome.  The  secondaiy  tubercles  are  very  abun- 
dant, and  limited  to  this  region  of  the  test ;  at  the  base  of  each  interambulacra  there  are 
six  short  rows,  a  long  and  a  short  row  between  the  zones  and  the  tubercles  on  each  side, 
and  two  short  rows  between  the  tubercles  themselves.  This  great  profusion  of  small 
secondary  tubercles  and  diminished  size  of  those  in  the  primary  series  impart  to  the  base 
of  the  test  of  this  Urchin  a  remarkable  ornamental  appearance,  which  resembles,  on  a  larger 
scale,  the  structure  of  the  base  in  P.  JRJiodani  (fig.  3  h). 

The  miliary  zone  is  largely  developed ;  the  two  primary  rows  of  tubercles  at  the 
ambitus  have  six  rows  of  granules  forming  a  band  between  them ;  in  the  upper  part  the 
gi-anulation  increases,  and  fills  the  whole  zone,  except  the  part  occupied  by  the  areolas  of 
the  small  rudimentary  tubercles,  forming  circles  around  them,  and  filling  the  whole  space 
with  a  fine  nearly  uniform  granulation. 

The  base  is  very  concave  and  crowded  with  small  tubercles ;  the  mouth-opening  is 
small,  and  lies  at  the  bottom  of  a  very  deep  depression ;  the  peristome  is  narrow,  and 
marked  by  feeble  indentations. 

Affinities  and  Differences. — This  remarkable  species  resembles  P.  Itliodani  in  having  its 
base  crowded  with  numerous  small  tubercles,  and  in  having  large  tubercles  at  the  ambitus, 
and  rudimentary  ones  on  the  upper  surface.  Its  form,  however,  is  always  inflated ;  the 
poriferous  zones  are  straight  at  the  base  and  upper  surface,  and  undulated  at  the  ambitus. 
The  secondary  tubercles  are  larger  and  more  numerous,  and  distinguished  with  difficulty 
from  those  of  the  primaiy  rows  of  the  imder  surface. 

Locality  and  Stratigrapldcal  Position. — The  only  specimen  I  have  seen  was  obtained 
from  the  Grey  Chalk  near  Folkestone  by  the  Rev.  T.  Wiltshire,  to  whose  cabinet  it 
belongs. — Foreipi  Distribution. — M.  Cotteau  records  Yimoutiers  (Orne),  in  the  Etage 
Cenomanien,  where  it  is  very  rare. 


PROM  THE  GREY  CPIALK. 


107 


PSETJDODIADEMA  .ARioLARE,  Brongniart,  sp.,  1822.     PI.  XVII,  figs.  1-5  ;  XVIII, 

figs.  1,  2. 


Bronyniart.  Geog.  phys.  des  env.  de  Paris,  pi.  v,  fig.  9, 
1822;  Tableau  des  Terrains,  p.  408,  1829  ;  Desc. 
g^ol.  des  eiiy.  de  Paris,  3' edit.,  pi.  xvii,  fig.  9,  1835. 

Agassiz.     Prod,  d'une   Monogr.  des  Radiaires,  p.   189, 

1836. 
Boemer.     Norddeutsclien  Kreidegebirges,  p.  29,  1840. 
Morris.     Catalogue  of  British  Fossils,  p.  51,  1843. 
Agassiz  ttHesor.     Catalogue  rais.   des  Echinides,  Ann. 

des  Sc.  Nat.,  3=  ser.,  t.  vi,  p.  350,  1846. 
Agassiz  et  Ttesor.     Ibid. 
Agassiz  et  Desor.     Ibid. 

Bronn.     Index  Paleeontologicus,  p.  1261,  1848. 
A.  Gras.     Oursins  foss.  de  I'Isfere,  p.  33,  pi.  ii,  fig.  16, 

1848. 
D'Orbigng.     Prod,  de  Paleout.  strat,,  t.  ii,  p.  179,  1850. 
D'Orhigmj.     Ibid.,  t.  ii,  p.  201. 
Sorignet.     Ours.  foss.  de  I'Eure,  p.  26,  1850. 
B'Archiac.     Hist,  des  progres  de  la  Geol.,  t.  iv,  p.  215^ 

1851. 
Quenstedt.     Handbuch  der   Petrefaktenkunde,   p.  580, 

1852. 
Giehel.     Deutschlands  Petrefacten,  p.  319,  1852. 
Forbes.     In  Morris's  Catalogue  of  British  Fossils,  2nd 

ed.,  p.  77,  1854. 
Forbes.     Ibid. 
Besor.     Synopsis  des  Echinides  fossiles,  p.  78,  1856. 

Besor.  Ibid. 
Besor.  Ibid. 
Woodward.     Mem.  Geol.  Survey,  Decade  V,  1856. 

Woodward.     Ibid. 

Pictef.     Trait6  de  Paleont.,  T  ed.,  t.  It,  p.  215,  1857. 

Pictet.     Ibid. 

Coquand.     Synop.    des    Foss.  Cretaces,   Bulletin   See. 
Geol.  de  France,  2'  s6r.,  t.  xvi,  p.  992,  1859. 
—  SUBNUDTJM,  Coqitand.     Ibid.  ,      ,      q    .u 

PsErDODiADEMASTUiATTTLUM,  Cotteau  et  Triger.     Echin.   du   depart,  de    la   Sarthe, 

p.  144,  pi.  xxxvii,  figs.  13 — 15,  1859. 
PSEUDODIABEMA  RoissYi,         Cotteau  ti  Triger.     Ibid. 

DiPLOPODiA  VAKioLABis,  Coquand.     Cat.  rais  des  Foss.  depart.  Charente,  p.  15o, 

1861. 


CiDABITES  VARIOLARIS, 

DiADEMA  VAKIOLARE, 

CiDARITES  TABIOLARIS, 
DiADEMA  VARIOLABE, 


—  SUBNUDUM, 

ROISSYI, 

Tetragramma  variolare, 

DiADEMA  — 

—  SDBNUDUM, 

KOISSYI, 

Tetagramma  subnddtjm, 
cidabis  variolaris, 

DiADEMA  VARIOLARE, 

Tetkagramma  — 

DiADEMA  SUBNUDUM, 

—  VARIOLARE, 
DiPLOPODIA  VARIOLARIS, 

SDBNUDA, 

RolSSYI, 

DiADEMA  VARIOLABE, 

SUB-NUDUM, 

ROISSYI, 

DiPLOPODIA  VARIOLARIS, 


108  PSEUDODIADEMA 

DiPLOPODiA   SUBNUDDM,  Coquaitd.     Ibid. 

—  VAUioLARis,         Bujardin  et  Hupe.     Hist.  Nat.  des  Zooph.  Echinoderraes, 

p.  501,  1862. 

—  SUBNUDA,  Dvjardin  et  Hupe.     Ibid. 

—  STEIATULUM,         Dujardiii  et  Hupe.     Ibid. 

PsEUDODiADEMA  VAKIOLARE,  Cotteau.     Pak'ontologie  Fran9aisp,  Terrain  Crc'tace,  t.  vii, 

p. 488,  pis.  1117,  1118,  lll!),and  1120,figs.  1—3,  1864. 

Test  large,  subcircular,  slightly  subpentagonal,  nearly  equally  depressed  on  the  upper 
and  under  surfaces.  Ambulacral  areas  narrow  and  contracted  at  the  upper  part  by  the 
poriferous  zones;  two  rows  of  tubercles,  15 — 17  in  each  series,  separated  by  a  single  line 
of  granules  ;  pores  round,  in  oblique  single  pairs  in  the  middle,  widely  bigeminal  on  the 
iipper  surface,  and  trigeminal  near  the  peristome.  Inter-ambulacral  areas  wide,  with 
four  rows  of  primary  tubercles  and  two  short  rows  of  small  secondary  tubercles.  The 
middle  of  the  upper  surface  of  the  area  nude  and  often  depressed.  Under  surface  convex, 
mouth-opening  small ;  peristome  with  feeble  entailles.  Discal  opening  large,  sharply 
angular,  pentagonal. 

Dimensions. — a. — Height  half  an  inch  ;  transverse  diameter  one  inch.  b. — Height 
half  an  inch ;  transverse  diameter  one  inch  and  a  half. 

Description. — The  identity  of  this  species  has  long  been  uncertain  from  the  impos- 
sibility of  ascertaining  the  Urchin  intended  by  the  figure  and  description  given  by 
Brongniart,  without  reference  to  the  type  specimen ;  this  comparison  has  now  fortunately 
been  made  by  M.  Cotteau,  who  has  given  admirable  figures  and  most  ample  descriptions 
of  the  various  forms  P.  variolare  exhibits  under  different  conditions  of  age  and  habitat.  I 
shall  first  describe  the  general  characters  of  the  species,  and  secondly  point  out  the  three 
chief  varieties  it  assumes. 

The  test  is  of  medium  size,  subcircular,  sometimes  lightly  pentagonal,  and  equally 
depressed  at  both  poles.  The  ambulacral  areas  are  narrow,  and  contracted  at  their  upper 
part  bythe  excessive  development  of  the  poriferous  zones  in  this  region;  they  possess  two  rows 
of  large  tubercles,  15 — 17  in  each  series,  according  to  size  and  age,  which  gradually  diminish 
in  size  from  the  equator  to  the  peristome,  and  become  small  and  rudimentary  on  the  upper 
surface  (PI.  XVII,  fig.  3  a).  The  rows  are  closely  approximated,  there  being  only  a  single 
series  of  small  granules,  of  unequal  size,  forming  a  zigzag  line,  between  them ;  the 
tubercles  have  narrow  areolas,  prominent  bosses,  with  sharply  crenulated  summits,  and 
deeply  perforated  mammillons  (fig.  4).  The  poriferous  zones  are  narrow,  the  pores 
round,  in  single  oblique  pairs  on  the  sides,  in  triple  oblique  pairs  near  the  peristome,  and 
they  are  widely  bigeminal  in  all  the  upper  fourth  of  the  zones  (fig.  5  a). 

The  interambulacral  areas  are  nearly  four  times  as  wide  as  the  ambulacral  in  the  spe- 
cimen figured  in  PI.  XVII,  figs.  3  a,  h,  c,  rather  more  than  one  inch  in  diameter.  There 
are  four  rows  of  large  tubercles,  and  two  secondary  rows,  at  the  ambitus ;  the  two  inner 
primary  rows,  with  fourteen  tubercles  in  each  series,  extend  from  the  peristome  to  the  apical 


FROM  THE  GREY  CHALK.  109 

disc,  and  the  outer  primary  rows  are  absent  from  the  three  uppermost  plates  (fig.  3  a).  In  a 
large  specimen  from  the  Chalk-Marl  of  Dorset,  b,  one  and  a  half  inches  in  diameter,  the 
ambital  plates  have  six  and  eight  rows  of  large  tubercles,  and  two  rows  of  small  secondary 
tubercles.  There  are  sixteen  tubercles  in  each  inner  series  which  alone  reach  the  disc, 
the  second,  third,  and  fourth  rows  disappear  as  the  plates  shorten  on  the  upper  surface. 
The  small  secondary  tubercles,  situated  near  the  poriferous  zones,  form  a  short  series 
between  the  peristome  and  equator;  they  are  scarcely  larger  than  granules,  but  are, 
nevertheless,  mammillated  and  perforated,  and  their  presence,  position,  and  development, 
constitute  one  of  the  specific  characters  of  this  Urchin.  The  interambulacral  tubercles 
are  nearly  identical  in  size  with  those  of  the  ambulacral  areas  (fig.  4).  They  have  narrow 
areolas,  prominent  bosses,  with  sharply  crenulated  summits,  and  large  perforated  mamil- 
lons.  The  miliary  zone  is  narrow  at  the  sides  and  infra-margin,  with  two  rows  of  granules 
of  unequal  sizes ;  at  the  upper  surface  it  becomes  nude  and  depressed  (fig.  3  a)  around  tlie 
discal  opening,  a  character  which  appears  in  excess  in  the  var.  suhimdum.  A  number 
of  granules,  of  different  sizes,  form  hexagonal  circlets  around  the  areolas  (fig.  5  a). 

The  under  surface  is  convex,  and  the  small  mouth-opening  occupies  a  slight  depres- 
sion ;  the  peristome  is  circular,  and  its  margin  notched  with  feeble  entailles  (fig.  3  b).  The 
opening  for  the  apical  disc  was  very  large  (fig.  3  a),  widely  pentagonal,  and  sharply  angu- 
lar, extending  into  the  nude  portion  of  the  inter-ambulacra.  None  of  the  specimens  as  yet 
found  contain  any  of  the  discal  plates.     (See  likewise  PL  XVHI,  figs.  1  a,  h,  and  fig.  2). 

Authors  have  recognised  three  distinct  forms  of  this  species,  which  some  have  de- 
scribed as  so  many  separate  species,  whilst  others  regard  them  as  varieties  of  one. 

1st.  Var.  a,  variolar e,  identical  with  Brongniart's  type  form,  is  found  in  the  Upper 
Greensand  of  Wiltshire  and  the  "  Chloritic  Marl "  of  Chard  (PI.  XVIH,  fig.  2)  and  I'Etage 
Cenomanien  of  Villers-sur-Mer,  Calvados,  Prance,  from  which  localities  I  have  specimens. 
Its  upper  surface  is  more  or  less  depressed,  and  its  outline  is  circular  or  subpen- 
tagonal.  The  inter-ambulacra  have  four  rows  of  primary  and  two  rows  of  small  secondary 
tubercles ;  the  under  surface  is  convex,  and  the  mouth-opening  small. 

2nd.  The  var.  h,  subnudum,  has  the  upper  surface  remarkably  nude,  from  the  ab- 
sence of  granules  in  the  upper  part  of  the  miliary  zone ;  the  test  is  higher,  and  my 
specimen  from  the  "  Chloritic  Marl "  of  Chard  has  a  thicker  structure  than  var.  a. 

3rd.  The  var.  c,  Boissi/i,  is  still  higher  and  much  larger  than  var.  b ;  it  has  a  more 
tuberculous  appearance,  and  from  six  to  eight  rows  of  tubercles  in  the  inter-ambulacra.  I 
have  two  specimens  before  me  that  agree  very  well  with  M.  Desor's  diagnosis  of  this 
form,  which  he  considers  a  good  species,  or  at  all  events  a  large  variety  of  P.  subnu- 
dum. After  a  critical  study  of  all  these  forms,  I  can  find  no  good  structural  character  for 
separating  them,  and  therefore  consider  them  as  varieties  of  P.  variolare,  depending  on 
age  or  habitat  for  the  differences  they  exhibit  in  the  size,  thickness,  and  number  of  tuber- 
cles in  the  inter-ambulacral  areas. 

AJuiities  and  Differences, — Pseudodiadema  variolare  is  one  of  the  most  perfect  types  of  a 


no  PSEUDODIADEMA 

tetragrammous  Diadema  with  bigeminal  pores.  It  very  much  resembles  P.  Brongniarti, 
Agas.,  from  the  Grey  Chalk,  but  is  distinguished  from  the  latter  by  having  its  upper  and 
under  surfaces  more  depressed,  the  ambulacral  areas  narrower,  their  rows  of  tubercles 
shorter,  and  those  on  the  upper  surface  more  rudimentary;  the  poriferous  zones  are  much 
wider  on  the  upper  foiu-th,  and  have  the  pores  more  largely  bigeminal ;  the  base  likewise 
is  more  convex,  wider,  and  less  contracted  than  in  P.  Brongniarti. 

Locality  and  Stratigraphical  Position. — P.  variolare  is  found  in  the  Upper  Greensand 
of  Warminster,  and  the  "  Chloritic  Marl "  near  Chard ;  from  the  latter  locality  I  have 
specimens  that  represent  the  var.  h.,  subnudam,  and  var.  c,  Boissi/i.  The  large  specimen 
was  kindly  communicated  by  the  Rev.  C.  W.  Bingham,  of  Binghams  Melcombe,  near 
Dorchester;  it  was  collected  from  the  Upper  Greensand  of  that  neighboui'hood — the 
precise  locality  is  not  recorded. 

Foreign  Localities. — M.  Cotteau  has  given  a  wide  range  to  the  distribution  of  this 
species  in  France,  and  records — "  Villers-sur-Mer,  Cauville,  Vaches-Noires,  Dives,  Saint- 
Jouin  (Calvados) ;  Octeville  (Manche) ;  Fecamp,  Le  Havre,  Rouen  (Seine-Infcrieure) ; 
Vimoutiers,  Grace,  La  Perriere  (Orue) ;  Presagny  pres  Vernon  (Eure) ;  Berneuil  (Oise) ; 
Grandpre  (Ardennes) ;  La  Fauche  pres  le  Villard-de-Lans  (Isere) ;  Le  Mans,  La  Raglasse, 
Yvre-l'Eveque  (Sarthe) ;  Corze  (Maine  et  Loire) ;  Touvois  (Loire-Inferieure) ;  Angouleme 
(Charente) ;  ile  Madame,  Saintes  (Charente-Inferieure).  Assez  abondant.  Etage  Ceno- 
manien,  commun  surtout  dans  la  zone  a  Scapldtes  ceqiialis. — Lillebonne  (Seine-Inferiem'e). 
Rare.     Etage  turonien." 

In  the  Hils  conglomerate,  near  Essen,  Hanover.     Desor. 

Uistorg.- — Figured  for  the  first  time  by  Brongniart  in  1822,  as  Cidarites  variolaris,m 
his  '  Geognosie  Physique  des  Environs  de  Paris,'  from  a  specimen  collected  at  Havre  in 
the  Upper  Greensand. 

In  the  '  Catalogue  raisonne  des  Echinides,'  1846,  MM.  Agassiz  and  Desor  separated 
certain  varieties  of  this  species  from  the  type  which  they  found  in  the  museums  of  France, 
under  the  names  Diadema  subnudum  and  D.  Boissgi ;  those,  however,  I  have  endeavoured 
to  demonstrate  are  merely  varieties  of  P.  variolare. 


FROM  THE  GREY  CHALK.  HI 


PsEUDODiADEMA  Brongniarti,  Ayasisiz,  1840.      PI.  XX,  fig.  2  a — c;  XXI  a,  figs,  i 

a—f,  3,  4 ;    XXI  B,  figs.  1—3  a—e. 

Tetkagramma  Brongniarti,  Agassi:.     Desc.  des  Echinides  fossiles  de  la  Suisse,  t.  ii, 

p.  25,  pi.  xiv,  figs.  4—6,  1840. 

—  —  Agassiz  et  Besor.     Catal.  rais.  des  Echinides,  Ann.  Sc. 

Nat.,  3e  ser.,  t.  vi,  p.  350,  1846. 

—  —  Bronn.     Index  Palseontologicus,  p.  1261,  1849. 
Diadema                    —  D'Orbigny.     Prodrome,  t.  ii,  p.  142,  Et.  19,  No.  328, 

1850. 

—  —  Renevier.     Mem.  Geol.  sur  la  Perte  du  Rhone,  p.  32, 

1853. 

—  —  Forhes.     In  Morris's  Catalogue  of  British  Fossils,  2nd 

ed.,  p.  76,  1854. 
PsEUDODiADEMA        —  Desor.     Synopsis  des  Echinides  fossiles,  p.  74,  1856. 

Diadema  —  Woodward.     Mem.  of  the  Geol.  Surv.,  Decade  V,  1856. 

_  _  Pictet.     Traite  de  Paleontol.,  2e  ed.,  t.  iv,  p.  244,  1857. 

Pseldodiadema        —  Bvjardin  et  Hitpi.      Hist.  Nat.  des  Zoophytes,  Echino- 

dermes,  p.  498,  1862. 
—  —  Cotteau.    Paleontologie  Francaise,  Terrain  Cretace,  t.  vii, 

p.  456.,  pi.  1109,  1865. 

Test  large,  subcircular,  elevated;  sides  tumid,  depressed  at  the  upper  surface,  narrow, 
rounded,  and  contracted  on  the  under  surface ;  ambulacral  areas  narrow,  with  two  rows  of 
tubercles,  separated  by  a  double  series  of  small  granules  of  unequal  sizes;  poriferous  zones 
narrow,  straight ;  pores  round,  in  single  pairs  from  the  peristome  to  the  ambitus,  and 
bigeminal  thence  to  the  disc-opening ;  inter-ambulaeral  areas  wide,  with  four  rows  of 
primary  tubercles,  nearly  identical  in  size  with  those  of  the  ambulacra,  and  two  short 
rows  of  very  small  secondaries  near  the  zones.  Mouth-opening  small,  in  a  considerable 
depression ;  peristome  narrow,  with  feeble  and  nearly  equal-sized  entaillcs. 

Dimensions. — a. — Height  six  tenths  of  an  inch  ;  transverse  diameter  one  inch  and  a 
half.     B. — Transverse  diameter  two  inches  and  a  half. 

Description. — The  test  of  this  species  exhibits  so  close  a  resemblance  in  many  of  its 
anatomical  details  to  that  of  Pseudodiadema  variolare,  that,  were  it  not  for  some  differences 
in  the  size,  shape,  and  development  of  the  shell,  and  in  the  structure  of  the  ambulacra,  I 
should  hesitate  to  separate  it  from  that  form ;  after  all,  these  differences  may  not  be 
specific,  but  may  have  arisen  from  habitat  and  other  physical  conditions.  A  test  of  each 
species,  with  spines  attached,  for  the  purpose  of  comparison,  is  still  with  me  a  desideratum  ; 
however,  as  this  Urchin  is  considered  by  most  authors  to  be  distinct  from  P.  variolare,  I 
shall  describe  the  fossils  I  have  figured  under  the  name  P.  Bronpiiarti,  Agas.     These 


113  PSEUDODIADEMA. 

specimens  have  been  compared  with  typical  examples  from  the  Upper  Greensand  of 
the  Perte  du  Rhone,  and  identified  as  the  true  forms  of  P.  Brongniarti,  Agas. 

The  test  is  moderately  large,  sub-circular,  and  elevated ;  the  sides  are  tumid,  and  the 
upper  surface  is  flat ;  the  base  is  convex,  contracted  at  the  circumference,  and  having  the 
peristome  sunk  in  a  considerable  depression  (PL  XXI  a,  fig.  2  c).  The  ambulacral  areas  are 
narrow,  and  sharply  lanceolate ;  they  have  two  rows  of  primary  tubercles,  from  sixteen  to 
seventeen  in  each  row,  which  diminish  gradually  from  the  ambitus  to  the  peristome  and 
the  disc  j  they  are  placed  closely  together,  and  have  narrow  ring-like  areolas  ;  the  bosses 
are  stout,  with  sharply  crenulated  summits,  and  the  mammillons  are  large  and  perforated 
(fig.  2  e) ;  a  row  of  granules,  of  unequal  sizes,  sometimes  mammillated,  separates  the 
tubercles  at  the  middle  and  base  of  the  area,  whilst  in  the  upper  part  branches  of  fine 
granules  pass  off  horizontally,  forming  circlets  around  the  tubercles  (fig.  2  e).  The 
poriferous  zones  are  narrow ;  the  pores  are  in  single  pairs  in  the  middle  and  infra-marginal 
region,  near  the  peristome  they  lie  in  triple  oblique  pairs,  above  the  ambitus  they  fall  out  of 
their  regular  ranks,  and  at  the  upper  surface  are  distinctly  bigeminal  (PI.  XXI  a,  fig.  2  h). 

The  inter-ambulacral  areas  are  more  than  twice  the  width  of  the  ambulacral ;  they 
have  four  rows  of  primary  tubercles  nearly  identical  with  those  in  the  ambulacra.  The 
two  inner  rows  are  best  developed,  and  extend  from  the  peristome  to  the  disc,  whilst  the 
external  rows  are  absent  from  the  three  uppermost  plates  ;  in  the  large  specimen  there 
mustha\'e  been  sixteen  to  eighteen  tubercles  in  each  internal  row  (PI.  XX,  figs.  2  a  and  h) ;  a 
series  of  small  unequal  secondary  tubercles  ascends  from  the  peristome  to  above  the  ambitus, 
situated  between  the  primary  tubercles  and  the  zones  (PI.  XXI  a,  figs.  2  d,  e) ;  they  are 
altogether  absent  from  the  upper  surface,  but  constant  in  the  region  I  have  described. 
The  miliary  zone  is  narrow  in  the  infra-marginal  region,  wider  in  the  middle,  and 
expands  at  the  upper  surface  ;  it  is  filled  with  four  rows  of  small  irregular  granules,  among 
which  a  number  of  small  mammillated  tubercles  as  large  as  the  secondaries  are  placed  (PI. 
XXI  A,  fig.  2  e) ;  above  the  ambitus  horizontal  branches  of  granules  extend  from  the  median 
rows,  separating  the  areolas,  and  forming  hexagonal  divisions  between  them  (fig.  2  e) ; 
at  the  upper  fourth  of  the  area  the  granules  disappear  from  the  middle  of  the  zone,  and  a 
triangular  nude  space  is  exposed,  having  its  base  at  the  disc  and  its  apex  at  the  fifth 
plate  ;  the  circlets  of  granules  are  absent  from  the  areolas  of  these  plates. 

The  upper  surface  is  flat,  and  the  opening  for  the  apical  disc  large  and  pentagonal,  the 
angles  extending  into  the  inter-ambulacra  (fig.  2  6.) 

The  base  is  convex  and  contracted  at  the  side ;  the  centre  is  concave,  about  one  third 
the  width  of  the  shell,  and  the  mouth-opening  lies  in  a  considerable  depression  ;  the 
peristome  is  small,  about  one  third  the  width  of  the  shell ;  in  a  fine  test  showing  the  base 
one  and  a  half  inch  in  diameter ;  that  of  the  peristome  is  half  an  inch  (fig.  2  c). 

Affinities  and  Differences. — P.  Brongniarti  is  distinguished  from  its  congeners  by 
its  elevated  test,  with  tumid  sides,  flat  upper  surface,  and  contracted,  convex  under 
surface. 


THE 


paltEontographical  society. 


INSTITUTED  MDCCCXLVII. 


VOLUME   FOE   1869. 


LONDON: 

MDCCOLZX. 


A    MONOGRAPH 


ON    THE 


BRITISH     FOSSIL 


ECHINODERMATA 


FROM 


THE  CRETACEOUS  FORMATIONS. 


THOMAS  WRIGHT,  M.D.,  F.R.S.  Edin.,  F.G.S., 

CORRESPONDING    MEMBER  OF   THE    ROYAL   SOCIETY   OF  SCIENCES  OF   LIEGE,   THE   SOCIETY   OF 
NATURAL  SCIENCES    OP   NEUFCHATEL,   AND    SENIOR   SURGEON   TO 
•  THE    CHELTENHAM    HOSPITAL. 


VOLUME    FIRST. 

PART  THIRD. 
ON   THE   DIADEMADiE. 

Pages  113—136 ;  Plates  XXU— XXIX,  XXIXa,  XXIXb. 

LONDON: 

PRINTED   FOR  THE   PAL^ONTOGRAPHICAL   SOCIETY. 

1870. 


PBIHTBD  BT 
.T.    E.    ADLAHD,  BARTHOLOMEW    CLOSE. 


FROM  THE  GREY  CHALK.  113 

The  pores  are  scarcely  bigeminal  near  the  summit.  The  primary  tubercles  are 
numerous,  nearly  uniform  in  size,  and  closely  set  together ;  the  mouth-opening  is  very 
small,  and  lies  in  a  deep  depression. 

Pseudodiadema  variolare  has  the  test  in  general  more  depressed,  the  base  wider,  and 
the  pores  more  distinctly  bigeminal  in  the  upper  fourth  of  the  zones ;  the  base  is  wider, 
more  convex,  and  less  contracted  than  in  Ps.  Bronpniarti. 

LocalHy  and  titrati(/raphical  Position. — Pseudodiadema  Bron(jniarti  has  been  col- 
lected from  the  Grey  Chalk  near  Folkestone,  from  which  stratum  all  the  large  tine  speci- 
mens in  the  British  Museum,  and  those  in  the  Rev.  T.  WiUshire's  cabinet  figured  in 
this  Monograph,  have  been  obtained.  The  Red  Chalk  of  Hunstanton  Cliff  has  yielded 
a  few  examples,  two  of  which,  from  Mr.  Rose's  and  the  Rev.  T.  Wiltshire's  collections, 
are  figured  in  PI.  XXI  b.  Forms  referred  to  this  species  have  been  collected  from 
the  Chalk-marl  of  Maiden  Bradley,  Dorset,  and  the  Chloritic  Marl,  Somerset. 

Foreign  Localities. — Professor  Pictet,  of  Geneva,  kindlv  gave  me  several  type  speci- 
mens of  this  Urchin  collected  from  the  Gault  of  the  Perte  du  Rhone  (Ain),  which  so  much 
resemble  Professor  Agassiz's  figures  of  this  species  from  the  same  locality  that  my  speci- 
mens might  have  been  the  originals  of  the  drawings  in  his  '  Bchinodermes  foss.  de  la 
Suisse.'  It  is  found  likewise  at  Escragnolle  (Var),  Montngne  des  Fis  (Savoie),  where  it  is 
an  abundant  fossil  in  the  Etage  Albien  or  the  Gault.  M.  Desor,  in  addition  to  these 
localities,  gives  Clar  and  La  Presta,  as  places  where  this  species  is  abundant. 

History. — First  figured  by  M.  Al.  Brongniart^  in  his  '  Description  de  la  Perte  du  Rhone,' 
under  the  name  Cidariles  variolaris  {?),  as  a  characteristic  fossil  of  the  Craie  INIarneuse ; 
afterwards  (1S40)  it  was  described  and  figured  by  Professor  Agassiz  in  the  '  Echinodermes 
foss.  de  la  Suisse'  as  Tetrngramma  Brongniarti ;  afterwards  (1856)  it  was  removed  by 
M.  Desor  into  his  genus  Pseudodiadema,  where  it  now  remains. 


Genus — Pedinopsis,  Cotteau,  1803. 

Test  large,  round,  inflated,  sometimes  subconical.  Poriferous  zones  wide  and  straight ; 
the  pores  bigeminal  throughout,  forming  at  the  upper  surface  and  ambitus  two  distinct 
rows,  which  become  more  blended  together  at  the  infra-marginal  region,  and  are  distinct 
at  the  base.  Tubercles  of  both  areas  small,  and  nearly  the  same  size ;  summit  of  the 
boss  finely  crenulated,  and  the  raammillon  perforated ;  the  tubercles  disposed  in  regular 
rows,  the  number  varying  in  the  different  species,  and  always  diminishing  as  they 
approach  the  summit ;  coronal  plates  long,  narrow,  and  granular ;  mouth-opening  large, 
peristome  moderately  developed,  circumference  slightly  incised,  apical  disc  small,  sub- 
circular,  elements  feebly  united,  absent  in  the  specimens  known. 

'  'Description  geologique  des  Environs  de  Paris,'  troisieme  edition,  1835,  p.  174,  pi.  m,  fig.  9. 

15 


114  PEDINOPSIS 

This  genus  was  established  by  M.  Cotteau  in  his  memoiri  on  '  Les  Echinides 
des  Pyrenees,'  and  placed  near  PseudocUadema,  with  which  it  has  many  affinities ;  the 
tubercles  are  crenulated  and  perforated,  and  the  pores  bigeminal  throughout,  a  character 
which  is  in  part  possessed  by  Ps.  Broiipnarfi,  variolare,  &c.  It  has  affinities  with 
Salmacis  in  the  number  of  its  pores ;  in  this  genus,  however,  they  are  arranged  in  triple 
oblique  pairs,  whilst  in  Pedinopsis  they  are  regularly  bigeminal  throughout. 

The  original  specimen  was  collected  from  the  Neocomian  strata  of  Aude,  where  it  is 
rare ;  another  of  the  same  species  has  been  found  at  Caussols  (Var) ;  the  one  which  I 
now  figure  was  obtained  from  the  Chloritic  Marl  near  Chardstock,  Somerset. 


Pedinopsis  Wiesti,  WrigJd,  nov.  sp.     PI.  XIV,  fig.  1  ;  PI.  XXIX  a. 

Test  moderate  in  size,  circular,  inflated  at  the  sides,  convex  on  the  upper  surface,  and 
fiat  at  the  base ;  ambulacra  with  two  complete  marginal  rows  and  two  inner  incomplete 
rows  of  tubercles ;  inter-ambulacra  with  six  rows  of  turbercles  at  the  ambitus,  the  two 
central  of  which  are  complete,  and  the  four  lateral  incomplete  ;  tubercles  nearly  all  of  the 
same  size ;  pores  uniformly  bigeminal  throughout. 

Dimensions. — Height  one  inch  ;  transverse  diameter  one  inch  and  seven  tenths ; 
mouth-opening  six  tenths  of  an  inch. 

I)escnj)tion. — This  rare  Urchin  forms  the  type  of  a  new  genus,  established  by  my  friend 
M.  Cotteau  for  a  similar  rare  species  from  the  Neocomian  of  Caussols  (Var).  The  test  is 
of  moderate  size,  circular  at  the  ambitus,  inflated  at  the  sides,  convex  on  the  upper 
surface,  and  flattened  at  the  base.  The  arabulacral  areas  are  moderately  wide,  and  retain 
their  proportional  diameter  throughout  the  area ;  they  have  two  rows  of  marginal 
tubercles  of  small  size,  which  extend  from  the  peristome  to  the  disc  (PI.  XXIX  a,  fig.  1), 
and  are  very  regular  both  in  size  and  arrangement ;  between  the  base  and  upper  surface  two 
other  rows  occupy  the  centre,  so  that  this  area  at  the  ambitus  is  furnished  with  four  rows 
of  tubercles  (PI.  XXIX  a,  fig.  1  g),  the  two  inner  ro\vs  of  which  disappear  at  the  lower 
seventh  (fig.  1  h)  and  upper  third  of  the  areas  (fig.  1  d) ;  the  tubercles  are  nearly  all  of  the 
same  size ;  around  the  base  of  the  bosses  some  fine  granules  are  sparsely  distributed, 
which  form  impeifect  circlets  around  them  (PI.  XXIX  a,  figs.  1  d,  e,f,g,  h).  None  of 
the  marginal  rows  in  the  specimen  is  complete,  so  that  the  exact  number  in  each  series 
cannot  be  ascertained  ;  but  as  thirty  can  be  counted  in  one  incomplete  column,  six  more 
may  be  fairly  estimated  as  wanting  (fig.  1  a,  h,  c). 

The  poriferous  zones  are  moderately  wide,  and  very  uniform  in  diameter  throughout, 

1  "Echinides  foss.  des  Pyrenees,"  p.  16.  E.xtrait  du  '  Congres  scientifique  de  France,'  28' session, 
tenue  a  Bordeaux,  t.  iii,  pi.  ix,  1863. 


FROM  THE  CHLORITIC  MARL.  115 

expanding,  however,  near  the  mouth,  where  an  increased  number  of  holes  seem  ahnost 
completely  to  encircle  the  peristome  (fig.  1  h) ;  throughout  the  zones  the  pores  are  very 
regularly  bigeminal,  and  are  grouped  into  distinct  ranges,  the  small  plates  forming  these 
zones  being  beautifully  dovetailed  into  each  other  (figs.  1  d,  g,  h) ;  by  this  arrangement 
there  are  from  six  to  seven  pairs  of  holes  opposite  each  ambulacral  plate,  which  gives 
3G  X  6  =  216  pairs  of  holes  in  each  zone. 

The  inter-ambulacral  areas  are  rather  more  than  double  the  width  of  the  ambulacral ; 
the  individual  plates  are  long  and  narrow,  being  only  a  little  deeper  than  those  of  the 
latter ;  two  rows  of  tubercles  occupy  the  centre  of  the  plates,  and  extend  very  regularly  in 
size  and  disposition  from  the  peristome  to  the  disc ;  on  the  zonal  side  of  this  central  row 
a  second  row  extends  from  the  peristome  over  three  fourths  of  the  area,  and  between  the 
central  row  and  the  median  suture  there  is  another  row  of  the  same  length  ;  in  addition 
to  these  six  rows  a  few  additional  tubercles  are  introduced  at  the  zonal  and  median  sides 
of  the  widest  ambital  region  of  the  area.  I  have  shown  this  chaiacter  in  figs.  1  (/  and  h, 
and  the  gradual  disappearance  of  the  tubercles  in  the  upper  part  of  the  area  is  seen  in  figs. 
1  a  and  c,  and  in  its  lower  part  in  figs.  1  b  and  h  ;  between  the  tubercles  a  number  of 
small  granules  are  sparsely  distributed  over  the  surface  of  the  plates. 

The  tubercles  in  this  genus  are  very  uniform  in  size  and  structure  throughout  both 
areas ;  the  boss  rises  suddenly  from  the  surface  of  the  plate,  without  any  areolar  depres- 
sion ;  its  summit  is  very  finely  crenulated  only  where  it  closely  embraces  the  mammillon, 
which  is  small,  prominent,  and  perforated  at  the  summit ;  in  the  widest  part  of  the 
areas  the  granules  form  imperfect  circlets  around  the  tubercles,  and  an  increased  orna- 
mentation at  the  ambitus  and  base  ;  at  the  iipper  surface  they  become  more  sparse  in  the 
ambulacra  (fig.  1  d),  and  are  almost  entirely  absent  in  the  inter-ambulacra  (figs.  1  a,  c). 

The  mouth-opening  is  nearly  circular,  about  one  third  the  diameter  of  the  test  (fig.  b) ; 
the  peristome  is  slightly  incised  and  vmequally  divided,  the  ambulacral  being  much  longer 
than  the  inter-ambulacral  lobes,  allo\Aing  a  wider  space  for  the  development  of  pedal  pores 
around  the  peristome. 

The  apical  disc  is  absent,  and  the  upper  part  of  the  test  is  unfortunately  broken  off, 
so  that  no  indication  of  the  size  or  form  of  the  disc  remains  imprinted  on  the  mould. 

Affinitws  and  Differences. — The  only  two  species  of  this  genus  at  present  known 
are  Pedinopsis  Meridanensis,  Cotteau,  from  the  Neocomian  of  Aude ;  and  P.  Wiesti, 
Wright,  from  the  Chloritic  Marl  near  Chardstock.  These  Urchins  resemble  each  other 
very  much ;  P.  Meridanensis  (PI.  XXIX  a,  fig.  2^)  has  a  greater  number  of  tubercles ; 
and  they  are  likewise  larger  and  more  regulai'ly  disposed  on  the  plates ;  the  poriferous 
zones  are  wider,  and  the  holes  larger  than  in  P.  Wiesti.  The  bigeminal  character  of  the 
zones,  the  smallness  of  the  tubercles,  and  the  thinness  of  the  shell,  are  special  characters 
by  which  this  Urchin  can  be  readily  distinguished  from  all  other  congeners. 

1  Copied  from  M.  Cottcau's  '  PaMontologie  Franfaise,'  pi.  112.j,  for  comparison  witli  tlie  English 
species. 


116  ECHINOCYPHUS 

Locality  and  Slratiriraphical Position. — Tliis  specimen  was  collected  by  Mr.  Wiest,  from 
the  Chloritic  Marl  near  Charclstock,  Somerset,  whei'e  it  is  associated  with  several  species 
of  Echinida  that  are  characteristic  of  the  Upper  Greensand  formation. 

EcHiNocYPHUs,  Cotteau,  1860. 

Glyphoctphds  (pars),  Besor,  1856. 
Cyphosoma  (pars),  Woodward,  1857. 
EcHiNOCTPHUs,  Cotteau,   1860. 

Test  small,  circular,  moderately  high,  more  or  less  inflated  on  the  upper  surface,  very 
concave  at  the  base.  Poriferous  zones  straight,  and  composed  of  simple  pores  throughout. 
Ambulacra!  and  inter-ambulacral  tubercles  nearly  the  same  size  in  both  areas,  bosses 
crenulated,  mammillon  not  perforated.  In  many  specimens  the  ambulacra  have  only  one 
row  of  tubercles  instead  of  two,  their  normal  number. 

The  inter-ambulacral  plates  are  marked  at  the  base  with  more  or  less  well-marked 
sutural  and  hoi'izontal  impressions.  Peristome  moderately  large,  subcircular,  sunk  in  a 
depression,  and  provided  with  slight  lobes.  Apical  disc  unknown,  opening  elongated 
and  subpentagonal,  as  indicated  by  the  impression. 

This  genus  was  established  to  receive  certain  species  referred  by  some  authors  to  the 
genus  GlyjjJioci/phus,  by  others  to  Cyphosoma.  These  species,  according  to  M.  Cotteau, 
are  distinguished  from  Glyphocyphis  by  their  imperforate  tubercles,  their  horizontal  sutural 
impressions,  and  less  solid  apical  disc.  Their  crenulated  and  non-perforated  tubercles 
bring  them  into  near  relation  with  certain  species  of  Cyphosoma,  as  C.  Delamarrei  and 
C.  maynificum,  var.  sulcatum,  which  show  at  the  base  of  their  inter-ambulacral  plates  some 
traces  of  sutural  impressions ;  but  these  feeble  depressions,  however,  cannot  be  compared 
with  the  deep  horizontal  grooves  that  characterize  Echinocyphus,  and  impart  to  the  few 
species  composing  this  group  the  physiognomy  of  Glypihocypihus,  with  which  M.  Desor 
placed  them. 


Echinocyphus  difficilis,  Ayass.     PI.  XXII,  figs.  1  «,  i,  3  a,  b,  c,  d,  4. 

Cyphosoma  difficile,  Ayass.     Catal.  Syst.  Ectyp.,  Mus.  Neocom.,  p.  12,  1840. 

—  —  Agassis  et  Desor.     Catal.  rais.  des  Echinid.,  Ann.  Sc.  Nat., 

3e  serie,  tom.  vi,  p.  352,  1846. 

—  —  Bronn.     Index  Palieontologicus,  p.  381,  1848. 
DiADEMA  ROTULARE,             McCoij.      Mesozoic  Radiatft,    Ann.    of    Nat.    History    for 

December,  1848. 

—  Maccoyi,  Forbes.     Catalogue  of    British  Fossils,  Morris,  2ud  ed., 

p.  76,  1854. 

—  rotatum,  Forl/es.     JMeoioirs  of  Geological  Survey,  Decade  V,  p.  3, 

1856. 


FROM  THE  GREY  CHALK.  117 

Glyphocyphus  difficilis,  Desor.     Synops.  des  fichinides  foss.,  p.  104,  185". 

Cyphosoma  difficile,  Woodward  (pars).     Mem.  of  Geol.  Survey,  Appendix 

to  Decade  V,  p.  3,  1858. 
Glyphocyphus  difficilis,         Dujardin  et  Hupe.     Hist.  Nat.  des  Zooph.,  Echinid., 

p.  513,  1862. 
EcHiNOCYPHUS  difficilis,  Cotteau.      Pal.  Fran9aise,  Ter.  Cretace,  t.  vii,  p.  708, 

pi.  1174,  1866. 
—  EOTATUs,  CoMeaw  (pars).     Ibid.,  t.  vii,  p.  "11,  pi.  1174-/5. 

Test  small,  subcircular,  moderately  inflated  on  the  upper  surface,  flattened  at  the 
base,  concave  around  the  mouth,  and  rounded  at  the  sides ;  poriferous  zones  narrow, 
straight,  and  subflexuous  at  the  ambitus ;  pairs  of  pores  in  a  single  series ;  ambulacral 
areas  narrow  above,  enlarged  at  the  ambitus,  with  two  rows  of  tubercles,  one  of  which  is 
often  abortive ;  inter-ambulacral  areas  wide,  having  two  rows  of  tubercles ;  plates  pos- 
sessing small,  strongly  radiated  areolae,  and  divided  by  deep  sutural  impressions ;  apical 
disc  equal  to  the  oral  opening,  flat,  and  finely  granulated. 

Dimensions. — Transverse  diameter  eight  tenths  of  an  inch  ;  height  four  tenths  of  an  inch. 

Description. — This  Urchin  has  long  been  mistaken  for  a  Diadeiiia,  and  is  catalogued  in 
some  lists  of  Upper  Greensand  fossils  as  D.  rotatmn.  Small  specimens,  measuring  from  four 
to  five  lines  in  diameter,  are  abundant  in  the  Upper  Greensand  of  Warminster,  and  may 
readily  be  distinguished  from  Diademas  by  the  sutural  impressions  on  their  plates,  the 
small  radiating  ribs  on  many  of  the  large  areote,  and  the  irregularity  of  the  two  rows  of 
ambulacral  tubercles,  one  of  which  is  often  abortive.  The  larger  and  taller  specimens 
agree  with  the  published  mould  of  Professor  Agassiz's  type  specimen  of  Cyphosoma  dijficile, 
to  which  this  Urchin  is  now  referred. 

Almost  all  the  examples  I  have  collected  from  the  Upper  Greensand  are  small  and 
well  preserved ;  the  few  I  have  from  the  Lower  Grey  Chalk  are  larger,  and  show  the 
sculpturing  of  the  plates  better.  The  test  is  subcircular,  or  slightly  pentagonal,  mode- 
rately convex  on  the  upper  surface,  flattened  at  the  base,  and  rounded  at  the  border. 
The  poriferous  zones  are  narrow,  straight  above  and  below,  and  siibundulated  at  the 
ambitus.  The  pores  are  small,  and  form  a  single  series  of  pairs  throughout  from  the 
mouth  to  the  disc  (fig.  2  d) ;  the  pairs  of  pores  are  separated  horizontally  by  small  promi- 
nent ribs,  more  or  less  granular,  which  correspond  to  the  poriferous  plates,  and  are  pro- 
longed to  the  base  of  the  tubercles.  The  ambulacral  areas  are  narrow,  and  provided  with 
two  rows  of  tubercles ;  in  some  specimens  from  the  Grey  Chalk  these  rows  are  regular 
and  the  tubercles  of  equal  size,  but  in  many  specimens  from  the  Upper  Greensand, 
as  in  figs.  2  a,  b,  c,  d,  one  row  becomes  abortive,  and  the  other  only  is  developed ; 
more  than  half  the  specimens  that  have  passed  through  my  hands  have  been  thus 
formed.  The  inter-ambulacral  areas  are  wide,  with  two  rows  of  tubercles  a  little 
larger  than  those  occupying  the  ambulacra ;  in  large  specimens  there  are  ten  or  twelve 
tubercles  in  each  row,  the  number  depending  on  the  age  of  the  individual.  Between 
the    ambitus    and    peristome    the   areolas   are    well    developed,   and    surrounded    by 


lis  ECHINOCYPHUS 

circles  of  large  sul)- elliptical  granules,  that  are  prolonged  in  a  radiated  manner  towards 
the  base  of  the  mammillon  (fig.  3  d).  The  coronal  plates  at  their  lower  border  are 
marked  by  a  horizontal  depression,  as  if  the  lower  half  of  the  plate  had  been  scooped  out 
(fig.  2  a)  at  the  expense  of  a  portion  of  the  granular  circle.  The  boss  is  prominent, 
and  its  summit  is  marked  with  feeble  crenulations.  The  maramillon  is  always  large  and 
unperforated.  The  miliary  zone  is  wide  in  its  upper  part,  and  the  surface  of  the  plates  is 
covered  with  a  very  fine  granidation ;  at  the  ambitus  it  is  filled  with  two  or  three  rows  of 
large  granules,  which  diminish  below  into  a  single  series,  and  take  a  zigzag  direction 
towards  the  peristome. 

The  small  mouth-opening,  about  one  third  the  diameter  of  the  test,  is  lodged  in  a 
concave  depression  (fig.  2  b).  The  peristome  is  circular,  and  nearly  equally  lobed,  and 
the  incisions  are  slight. 

The  apical  disc,  which  is  very  rarely  preserved  (PI.  XXII,  fig.  4),  equals  the  oral 
opening  in  size,  and  is  flat  and  finely  granulated ;  the  cordate  ocular  plates  are  rather 
large,  and  perforated  close  to  the  ambulacral  margin ;  the  large  ovarial  plates  are  per- 
forated, and  the  madreporiform  body  occupies  the  right  anterior  plate  ;  the  single  posterior 
plate  is  wanting. 

Affinities  and  Differences. — This  species  very  much  resembles  Cypliosoma  rotatum,  Forb., 
of  which  it  proves  to  be  a  A'ariety  ;  the  irregularity  of  the  two  rows  of  ambulacral  tubercles, 
one  of  which  is  often  abortive,  is  not,  according  to  our  observations,  a  persistent  character, 
and  for  this  reason  we  regard  E.  dijjicilis  and  E.  rotatus  as  varieties  of  one  form.  M. 
Cotteau,  however,  considers  them  distinct,  and  takes  as  a  diagnostic  character  the  single 
row  of  tubercles  in  the  ambulacral  areas,  as  this  difference  does  not  appertain  to  age, 
seeing  that  it  is  found  in  small  as  well  as  in  large  speciuiens.  Echinoci/phus  difficilis, 
Ag.,  may  be  confounded  with  Gli/phoci/pJius  infermedius,  Cott.,  which  has  a  similar  dis- 
position of  the  ambulacral  tubercles,  only  that  they  are  perforated  in  Glijphocyplius 
and  vmperforated  in  Echinocyplms. 

Locality  and  Stratigrapliical  Position. — I  have  several  specimens  which  I  collected 
from  the  hard  Grey  Lower  Chalk  near  Folkestone,  and  numerous  smaller  examples  from 
the  Upper  Greensand  near  Warminster;  from  the  latter  foruiation  a  very  large  specimen 
was  obtained,  now  in  the  cabinet  of  G.  E.  Sloper,  Esq.,  Devizes.  The  late  Dr.  S.  P. 
Woodward  states  that  it  measures  nine  lines  in  diameter,  and  four  and  a  half  in  height ; 
both  rous  of  ambulacral  areas  are  well  developed,  and  the  miliary  granules  form  a 
prominent  framework  to  the  tubercles. 

In  France,  M.  Cotteau  records  this  species  from  the  Etage  Cenomanien  of  Vellclaire 
(liaute-Saone),  and  Presagny  (Eure),  where  it  is  rare. 

History. — First  catalogued  as  Diadcma  rolidare,  Ag.,  from  Durdle  Door,  Dorset,  by 
Prof.  McCoy,  in  his  '  Mesozoic  Radiata,'  in  1848,  and  afterwards  by  Prof.  E.  Forbes,  as 
Diadema  rotatum,  from  the  Upper  Greensand  of  Warminster,  in  the  second  edition 
of  the  '  Catalogue  of  British  Fossils.' 


FROM  THE  GREY  CHALK.  1J9 


EcHiNOCTPHUS  MESPiLiA,  Woodward.     PI.  XXn,  figs.  3  a,  h,  c,  d. 

Cyphosoma  MESPILIA,  Woodward.     App.  Decade  V,  Mem.  of  the  Geol.  Survey, 

p.  3,  1856. 

Test  small,  circular,  inflated  oi*  depressed,  convex  above  and  below,  with  subequal 
apertures ;  poriferous  zones  straight,  simple,  pairs  of  pores  very  ol)liqne ;  tubercles  nearly 
equal,  prominent,  imperforate  and  crenulated  ;  areolas  small,  radiated,  with  elongated 
miliary  granules,  sutural  impressions  slight;  inter-ambulacra  wide,  with  two  rows  of 
tubercles,  seven  to  eight  in  each ;  auibulacra  narrow,  with  seven  to  eight  tubercles,  alter- 
nate, and  irregular. 

Dimensions. — Height  three  lines ;  transverse  diameter  five  lines. 

Description. — This  species  was  discovered  by  my  late  friend,  Dr.  S.  P.  Woodward, 
who  found  it  in  the  Lower  Hard  White  Chalk  along  with  Cyphosoma  simplex,  Forb.,  and 
Salenia  gramdosa,  Forb.  It  is  a  pretty  little  Urchin,  with  inflated  sides ;  the  test  is  nearly 
convex  above  and  below,  the  poriferous  zones  are  straight  and  simple,  the  unigeminal 
pores  are  very  oblique,  the  ambulacral  areas  are  narrow,  and  the  tubercles,  seven  or  eight 
in  number,  are  alternate  and  irregular  (fig.  3),  one  of  the  rows  being  partially  abortive. 
The  inter-ambulacral  areas  are  wide,  and  have  two  rows  of  prominent  tubercles,  seven  to 
eight  in  each  row  (fig.  3),  which  occupy  the  centre  of  the  plates,  and  are  surrounded  by 
small  radiated  areolae,  formed  by  an  oblique  arrangement  of  the  elongated  granules 
thereon,  and  imparting  an  ornamented  character  to  the  test.  The  mouth-opening  is  more 
than  one  third  of  the  diameter  of  the  test,  the  peristome  is  nearly  equally  lobed,  and  the 
incisions  are  wide  and  deep.     The  discal  opening  is  larger  than  the  oral  in  diameter. 

Affinities  and  Differences. — This  Urchin  very  much  resembes  E.  difficilis ;  it  has, 
however,  a  more  inflated  test,  with  stronger  radii  on  the  areolae,  and  larger  oral  and  discal 
apertures.  Its  author  considered  it  "  a  very  distinct  species,"  and  called  ray  especial 
attention  to  it.  A  careful  comparison  of  the  accurate  figures  of  both  species  drawn  on 
PI.  XXII  will  enable  the  student  to  appreciate  the  affinities  and  differences  between  them 
better  than  any  description,  however  elaborate. 

Locality  and  Strati/jraphical  Position. — E.  mespilia  has  been  collected  only  from  the 
Lower  Chalk,  in  the  hard  beds  of  which  it  has  been  found,  associated  with  Cypihosoma 
simplex  and  Salenia  granulosa.  The  only  specimens  I  have  seen  are  in  the  British 
Museum. 


120  GLYPHOCYPHUS 


Genus — Glyphocyphus,  Haime,  1853. 

Arbacia  (pars),  Agassis,  ISSfi. 
EcHiKOPSis  (pars),  Agassiz,  1&46. 
Hemidiadema,  Agassis,  1846. 
Temnopleuea  (pars),  Sorignet,  18.50. 
GLYniociYPHCs,  Jules  Haime,  18.53. 

—  Besor,  18.56. 

—  Cotteau,  1839. 

The  Urchins  forming  this  group  have  a  small  circular  test,  more  or  less  inflated  above 
and  concave  below.  The  poriferous  zones  are  straight,  depressed,  and  composed  of  uni- 
geminal  pores  throughout.  The  primary  tubercles  of  both  areas  are  nearly  of  the  same 
size.  The  boss,  with  its  crenulated  summit,  is  surrounded  by  a  distinct  areola,  and  sur- 
mounted by  a  small  niammillon  minutely  perforated  at  the  vertex.  The  ambulacral  and 
inter-ambulacral  plates  are  marked  with  sutural  depressions,  which  are  wider  and  deeper 
on  the  plates  of  the  latter  areas ;  the  surface  is  covered  with  fine,  close-set  homogeneous 
granules,  nearly  uniform  in  size  over  the  whole  test  (PI.  XXIX  b,  figs.  1  and  2).  The 
apical  disc  is  a  small  annular  structure,  solidly  united  to  the  test,  and  forming  a  narrow, 
sHghtly  elongated,  oblong  ring,  composed  of  five  ovarial  and  five  ocular  plates,  articulated 
alternately  together  on  the  same  line  around  the  vent  aperture  or  periprocte  (fig.  2  b). 
The  ovarial  plates  are  the  largest ;  they  have  a  triangular  shape,  with  tubercles  external 
to  the  annulus,  and  a  large  hole  at  the  apex ;  the  right  antero-lateral  plate  is  the  largest, 
and  supports  the  niadreporiform  body.  The  rhomboidal  ocular  plates  are  wedged  in 
alternately  on  the  same  line  with  the  ovarials ;  and  the  portion  external  to  the  annulus  is 
covered  with  numerous  granules.  Mouth-opening  is  small,  subcircular,  and  sunk  in  a 
slight  depression  ;  peristome  decagonal,  divided  into  lobes  by  feeble  incisions. 

The  genus  G///p/ioc//jj/ais  forms  among  the  Diademad^  with  crenulated  and  perforated 
tubercles  a  very  small  group,  in  which  the  ambulacral  and  intcr-arabulacral  plates  are 
marked  with  angular  impressions,  and  their  surface  covered  with  prominent  close-set 
granulations.  The  solidity  of  the  apical  disc,  and  its  firm  articulation  to  the  coronal 
plates,  with  the  regularity  as  regards  size  and  arrangement  of  the  tubercles  in  both 
areas,  form  an  assemblage  of  characters  which  readily  distinguish  the  small  Urchins  of  this 
group  from  their  congeners.  A  considerable  difference  of  opinion  has  prevailed  amongst 
Echinologists  regarding  the  true  characters  of  the  forms  now  comprised  in  this  genus, 
arising,  doubtless,  from  the  smallness  of  the  individuals  themselves,  the  imperfect  pre- 
servation of  most  of  the  specimens,  and  the  destruction  of  many  of  the  essential  structures 
that  distinguish  them,     M.  Cotteau,  however,  had  lately  at  his  disposal  a  fine  series  of 


FROM  THE  GREY  CHALK.  121 

beautiful  and  perfect  specimens  of  Glyj)hocyphis  radiafus,  collected  by  the  late  M.  Triger 
from  the  Terrain  Cretace  of  the  department  of  the  Sarthe,  and  from  the  study  of  these 
M.  Cotteau  has  been  enabled  to  clear  up  doubts  that  had  previously  existed  regarding  the 
structure  of  many  of  the  species.  This  genus  is  nearly  allied  to  Echinocyphis,  which 
presents  a  similar  facies  of  lateral  impressions  on  the  ambulacral  and  inter-ambulacral 
plates,  but  is  distinguished  from  it  by  having  the  mammillons  of  the  tubercles  perforated, 
whereas  in  EcMnocyphus  they  are  imperforate.  The  apical  disc  is,  likewise,  solidly  united 
to  the  coronal  plates  in  Gli/phocyphus,  but  slenderly  so  in  EcMnocyphus.  M.  Agassiz 
proposed  the  genus  Hemidiadema  for  Urchins  differing  from  the  Diademas  in  one 
character,  that  the  ambulacral  areas  possessed  only  a  single  row  of  tubercles,  and  cited 
as  the  type  of  this  group  Hemidiadema  ?7((?os?«;?,  Agass.,  from  the  Upper  Greensand  (Etage 
Cenomanien)  of  Grandpre,  Ardennes,  a  small  species  having  the  ambulacral  tubercles 
as  large  and  even  larger  than  the  inter-ambulacrals ;  this  Urchin,  it  now  appears,  is  a  true 
Glyphocyphis,  with  a  single  row  of  tubercles  in  its  ambulacral  areas — a  character  which 
is  only  specific,  and  not  generic,  as  far  as  we  at  present  know. 

The  genus  Echinopsis,  Agass.,  in  which  certain  species  of  Glyphocyphus  have  been 
placed,  consists,  according  to  its  author,  of  "  small,  subconical,  inflated  Urciiins,  with  the 
ambulacra  nearly  as  large  as  the_  inter-ambulacra,  and  both  ornamented  with  tubercles 
perforated  but  not  crenulated.  Mouth  small,  with  feeble  incisions,  differing  from  the 
Diademas  by  the  absence  of  crenulations  on  the  tubercles."  To  this  genus  was  referred 
Echinopsis  contexta,  Ag.,  E.  latii^ora,  Ag.,  E.  depressa,  Ag.,  all  of  which  are  forms  of 
GIyp)hocypjhus  radiafus  and  Glypticus  KonincJcii,  Forb.  Echinopsis  pusilla,  Roem.,  and 
Temnopleurus  pulcheUiis,  Coquand,  must  now  likewise  be  added  to  the  list. 


GLYPHOcypHUS    RADiATUs,  IIoBnin(/haus.      PI.  XXIX  b,  figs.   1,   2,  a,  b,  c,  d,  e. 

t 

EcHiNDS  EADIATUS,  Homiiiffhaus  in  Gold/uss.     Petref.  Germanise,  p.  124,  tab.  xl, 

fig.  13,  182ti. 

—  —  Agassiz.      Prod.,  Mem.  Soc.  Nat.  des  Sc.  de  Neufchatel, 

t.  i,  p.  196,  1836. 

—  —  Desmonlins.     Etudes   sur  lea  Echinides,   p.  292,   No.   55, 

1S37. 
EcpiNOPSis  LATIPORA,  Agassiz.     Catal.  Syst.  Ectyp.  foss.,  Mus.  Neoc,  p  9,  1840. 

—  CONTEXTA,         Agassiz.     Ibid. 

—  DEPRESSA,         Agassiz.     Ibid. 

Echinus  badiatus,  Vujardin.     In  Lamarck's  Anim.  sans  Vert.,  2e  e'd.,  t.  iii, 

p.  371,  1840. 
Aebacia  radiata,  Roemer.     Norddeutschen  Kreidegebirges,  p.  30,  1840. 

Echinopsis  pusilla,  Roemer.     Ibid.,  pi.  vi,  fig.  10,  1840. 

Cyphosoma  radiatum,         Agassiz  et  Besor.     Ann.  Sc.  Nat.,  3e  surie,  t.  vi,  p.  352. 

Cat.  rais.  des  Bcbinides,  1846. 

16 


ECHINOPSIS  PUSILLA, 

Morris. 

—           LATIPORA, 

Pietet. 

CONTEXTA, 

Pictet. 

DEPRESSA, 

Pietet. 

PCSILLA, 

Pictet. 

Cyphosoma  badiatum, 

Pietet. 

Glyphocyphus  radiatus, 

Desor. 

122  GLYPHOCYPHUS 

EcuiNOPSis  LATIPORA,  Jgassiz  et  Desof.     Ibid.,  p.  351,  1 84G. 

—  CONTEXTA,  Agassiz  et  Desor.     Ibid. 

—  DEPRESSA,  Agassiz  et  Besor.     Ibid. 

—  CONTEXTA,  Bronn.     Index  Palseontologiciis,  p.  447,  1818. 

—  DEPRESSA,  Bronn.     Ibid. 

—  LATIPORA,  Bronn.     Ibid. 

—  PUSiLL.i,  Bronn.     Ibid. 

Arbacia  RADIATA,  Bronti.     Ibid.,  p.  91,  1848. 

TEMNOPLEUKUSPDLCHELLUSjiSor/jrne^.     Ours.  fossiles  du  Dep.  de  I'Eure,  p.  31,  1850. 
Glyptious  Koninckii,  Forbes.     la  Di.xon's  Geology  of  Sussex,  p.  340,  tab.  xxt, 

fig.  30,  1850. 
EcHiNOPSis  PDsiLLA,  Forbes.     In  Dixon,  ibid.,  tab.  xxv,  fig.  31,  1850. 

—  —  Giebel.     Deutschlaiids  Petrefacteu,  p.  320,  1852. 
Glyphocyphus  pulciiellus,  d'Archiac  et  Jules  Haime.    Descript.  Nummilites  de  I'liide, 

p.  202,  1854. 
Morris.     Catal.  of  Brit.  Fossils,  2nd.  ed.,  p.  78,  1854. 
Tiaite  de  Paleontol.,  2e  ed.,  p.  242,  1846. 
Ibid. 
Ibid. 
Ibid. 
Ibid. 

Synopsis  des  fichinides  fossiles,  p.  103,  tab.  xvii, 
figs.  1—3,  1856. 

—  —  Cotteau  et  Triger.     Eciiinides  du  de'p.  de  la  Sartlie,  p.  185, 
pi.  xxviii,  figs.  7 — 12,  1859. 

—  —  Dujardin  et  Hupe.     Hist.  uat.  des  Echinod.,  p.  513,  1862. 
Temnopleurus  pulchellus,  CojMarerf.     Geol.  et  Pal.  de  la  prov.  de  Constaiitine,  p.  294, 

1863. 
GLYPHOCYPnus  radiatus,     Cotteau.      Paleont.   Fi-an9.,  Ter.  Cretace',   t.  vii,   p.  535, 

pi.  1127,  1128,  1863. 


Test  small,  circular,  inflated,  subglobular,  rounded  at  the  border  and  concave  at  the 
base ;  ambulacra  very  narrow,  with  two  rows  of  tubercles,  alternate,  irregular.  Poriferous 
zones  narrow,  straight ;  simple  pores  in  single  oblique  pairs.  Inter-ambulacra  with  two 
rows  of  small  tubercles,  areolae  radiated,  plates  grooved  at  the  lower  border ;  apical  disc 
solid,  forming  a  narrow,  elongated,  subpentagonal  ring,  having  the  genital  and  ocular 
plates  almost  of  equal  length  ;  oculars  finely  granulated ;  vent  large,  oblong. 

Dimensions. — Height  five  twentieths  of  an  inch  ;  transverse  diameter  eight  twentieths 
of  an  inch. 

Description. — This  small  Urchin  has  been  a  great  puzzle  to  Palaeontologists,  as  proved 
by  the  long  Hst  of  synonyms  given  above.  The  test  is  circular,  inflated,  and  subglobular; 
rounded  at  the  sides,  and  concave  towards  the  base  (figs.  1  a,  b).  The  ambulacral  areas 
(fig.  2  e),  about  half  the  width  of  the  inter-ambulacral,  have  two  rows  of  smafl  tubercles,  which 
form  an  alternate  series  on  each  side  of  the  area ;  they  are  largest  at  the  ambitus,  smaller 


FROM  THE  GREY  CHALK.  123 

at  the  base  and  upper  surface  ;  they  are  feel)ly  developed  throughout,  and  finely  perforated 
at  the  summit ;  the  areote  are  regularly  spaced  out  and  placed  on  the  border  of  the  poriferous 
zones,  which  are  straight,  slightly  depressed,  and  formed  of  small  round  pores,  disposed 
in  single  oblique  pairs  throughout,  from  the  peristome  to  the  disc ;  the  pairs  of  pores 
are  separated  from  each  other  by  a  horizontal  granular  ridge  of  the  test,  which  is  more  or 
less  apparent  in  diff'erent  s])ecimens  ;  in  some  examples  one  of  the  rows  of  tubercles 
becomes  abortive ;  the  surface  of  the  area  is  filled  in  with  numerous  small  granules,  and  the 
ambulacral  plates  are  shghtly  marked  with  impressions  on  the  line  of  the  median  suture. 
The  inter-ambulacral  areas,  fig.  2  c/,  are  double  the  width  of  the  ambulacral,  and  provided  with 
two  rows  of  tubercles,  similar  in  structure  to,  but  larger  in  size  than,  those  of  the  ambulacra; 
the  areolae  occupy  the  centre  of  the  plates,  and  are  surrounded  with  a  close-set  granulation ; 
two  of  the  granules,  elongated  in  a  vertical  direction,  unite  the  contiguous  areolae,  which 
imparts  a  moniliform  character  to  well-preserved  tests  of  this  pretty  little  Urchin  ;  the  plates 
are  marked  with  impressions  more  or  less  deep  at  the  inner  and  outer  angles,  and  on  each 
side  of  the  vertical  filament  at  the  lower  part  of  each  plate  (fig.  1  c,  fig.  2  c). 

The  mouth-opening  is  small,  situated  in  a  slight  depression,  and  the  peristome  is 
delicately  incised  into  ten  unequal  lobes  (fig.  2  a). 

The  vent  is  large,  sub-elliptical  in  shape,  and  contracted  behind ;  the  apical  disc 
forms  a  narrow,  elongated,  subpentagonal  ring,  somewhat  peculiar  in  its  structure,  for 
instead  of  the  small  ocular  plates  being  wedged  in  between  the  larger  genitals,  they 
are  arranged  alternately  with  them  on  the  same  fine,  and  form  a  strong  ring  around  the 
elliptical  vent ;  the  genital  plates  are  a  little  larger  than  the  oculars,  and  have  two  small 
tubercles  on  their  surface ;  the  oculars  are  covered  with  a  fine  granulation,  and  the 
madreporiform  tubei'cle  is  conspicuous  by  its  spongy  surface  (fig.  2  h). 

This  Urchin  varies  much  in  size  ;  the  specimens  figured  by  Goldfuss,  Desor,  and 
Dixon,  with  those  I  possess,  are  all  small.  M.  Cotteau  has  given  elaborate  details  of  a 
larger  specimen  found  in  the  Department  of  the  Sarthe,  in  which  the  characters  of  the  test 
are  admirably  exhibited ;  they  are  beautifully  figured,  both  in  his  fine  plates  on  the  Echinides 
of  the  Sarthe,  and  likewise  in  those  in  the  '  Paleontohigie  Eran9aise,'  some  of  which  I  have 
copied  in  PI.  XXIX  b,  as  none  of  my  specimens  have  the  characters  so  well  preserved  as 
in  the  ])erfect  fossil  test  figured  by  my  friend. 

Jffiiiities  and  Differences. — Gbjpliocyphas  radiatus  is  so  rare  an  Urchin  in  the  English 
Chalk  that  it  is  not  likely  to  be  mistaken  for  any  other.  It  is  smaller  and  more  globular 
than  Ecliinocyphus  difficilis,  which  it  most  resembles,  and  has  the  tubercles  perforated,  the 
miliary  zone  wider  and  more  granular,  the  disc  smaller  and  more  solidly  united  to  the 
coronal  places  than  in  any  Ecliinocyphi. 

From  a  careful  examination  of  the  ample  materials  at  his  disposition,  M.  Cotteau  con- 
cludes that  the  large  examples  forming  the  type  of  the  species  represent  EcJiinopsis 
contexta,  Ag.,  and  exhibit  natural  impressions  either  deep  and  angular  or  linear  and 
attenuated.     Some  specimens,  less  inflated,  and  possessing  a  stronger  development  of  the 


124  ECHINOTHURIA 

vertical  filament  form  E.  latipora,  Ag.,  and  depressed  examples  with  the  median  impres- 
sion almost  absent  are  E.  depressa,  Ag.  A  careful  study  of  the  original  types  has,  liow- 
ever,  convinced  my  learned  friend  that  they  are  all  varieties  of  one  form,  and  not  distinct 
species. 

Locality  and  StratigrapMcal  Position. — This  species  is  found  very  rarely  in  the  hard 
beds  of  the  Lower  Chalk  near  Lewes,  in  Sussex,  and  in  the  Grey  Chalk  near  Folkestone. 
From  tliis  stratum  my  best  specimen  v^^as  collected  by  Captain  Cockburn,  R.A.,  to  whose 
kindness  and  liberality  I  am  indebted  for  the  example. 

The  Foreign  Localities  given  by  M.  Cotteau  are  Villers-sur-Mer,  Bruneval,  Saint- 
Jouin,  Vaches-Noires,  Dives  (Calvados) ;  Fecamp,  le  Havre,  Rouen  (Seine-Inferieure) : 
Gace,  La  Perriere  (Orne) ;  Nogent-le-Bernard  (Sarthe) ;  Saint-Fargeau  (Yonne)  ;  la 
Bedoule,  Cassis  (Bouches-du-Rhone).  In  all  these  localities  it  is  very  rare,  and  occurs 
in  the  Etage  Ccnomanien,  in  the  zone  of  Scaphites  cequalis,  which  is  the  equivalent  of  the 
English  Low'Cr  Grey  Chalk. 

Historj/. — This  species  was  found  in  the  Lower  Chalk  of  Essen  and  Gehrden,  West- 
phalia, and  was  first  figured  and  described  by  Goldfuss  in  his  '  Petrefacta  Germanise.' 
Since  that  time  it  has  passed  through  a  series  of  changes  which  are  most  correctly  read 
in  the  long  list  of  synonyms  introductory  to  this  article,  and  to  which  I  commend  the 
reader's  especial  attention. 


Genus — Echinothuria,^  Woodward,  1863. 

"  Test  globular  ?,  diameter  of  compressed  specimen  four  inches,  thickness  half  an  inch, 
lantern  projecting  half  an  inch  ;  composed  of  ten  segments  or  double  series  of  imbricating 
plates,  ornamented  with  obscure  miliary  granules  and  small  spine-bearing  tubercles,  a  few 
larger  than  the  rest ;  inter-ambulacral  plates  narrow,  slightly  curved,  with  the  convex  edge 
upwards  and  overlapping ;  the  alternate  plates  bearing  one  large  extero-lateral  tubercle, 
perforated,  and  surrounded  by  a  raised  ring  and  smooth  areola ;  largest  plates  measuring 
six  lines  in  length,  the  smallest  three  lines  or  less  (the  longest  in  second  specimen  equal- 
hng  seven  lines) ;  ambulacral  plates  seven  lines  long,  equalling  the  breadth  of  the  exposed 
portion  of  eight  plates,  similar  to  the  former,  but  curving  and  imbricating  downwards 
towards  the  dental  orifice,  and  having  two  small  plates,  each  perforated  by  a  pair  of  pores, 
intercalated  in  a  notch  of  the  middle  of  the  lower  margin;  a  third  pair  of  pores  perfo- 
rating the  plate  itself  a  little  external  to  the  centre ;  primary  tubercles  few,  irregularly 
distributed. 

1  "  Etymologists  need  not  trouble  themselves  about  the  derivation  of  this  name  ;  it  is  intended  merely  to 
express  the  dilemma  in  the  writer's  mind,  arising  from  imperfect  knowledge,  but  which  he  believes  to  have 
no  foundation  in  nature."— '  Geologist,'  vol.  vi,  p.  330. 


FROM  THE  WHITE  CHALK.  125 

"  Spines  of  three  kinds  ;  those  adhering  to  the  plates  minute  and  striated  ;  fragments  of 
larger  spines  (not  certainly  belonging  to  the  species)  striated,  annulated,  and  furnished 
with  a  prominent  collar  to  the  articular  end  (fig.  4) ;  the  third  kind  minute,  clavate,  and 
truncate,  articulated  to  a  slender  stalk  "  (fig.  5). 


EcHiNOTHURiA  FLORis,   Woodwcml} — PI.  XXIX  B,  figs.  3 — 5. 

EcHiNOTHURiA  FLORIS,  Woodward.     'Geologist,'  vol.  vi,  pp.  327 — 330,  1863. 

"  The  fossils  represented  "  in  PI.  XXIX  b  "  are  probably  only  fragments  of  the  original 
structure,  and  possibly  only  the  smaller  and  less  essential  portions  of  the  whole.  Never- 
theless, I  have  determined  to  publish  some  account  of  them,  although  at  the  risk  of 
committing  an  extravagant  error,  as  a  last  resort  towards  obtaining  more  complete  ex- 
amples or  suggestions  for  their  more  correct  interpretation. 

"  Both  specimens  have  been  presented  to  the  British  Museum ;  one  by  J.  Wickham 
Flower,  Esq.,  of  Park  Hill,  Croydon,  the  other  by  the  Rev.  Norman  Glass,  of  London. 

"  The  first  example  was  obtained,  at  least  sixteen  years  ago,  from  the  Upper  Chalk  of 
Higham,  near  Rochester,  and  was  submitted  to  Professor  E.  Forbes,  in  whose  custody  it 
remained  for  several  years.  It  was  originally  shown  to  me  in  connection  with  the 
anomalous  Cirripede  Loricida,  then  newly  discovered  by  Mr.  Wetherell.  The  resemblance 
between  them  is  certainly  curious  ;  but  there  is  no  real  relationship.  Mr.  Flower's  fossil 
exhibits  distinct  traces  of  the  crystalline  structure  peculiar  to  petrified  Echinodermata, 
and  the  pairs  of  pores  in  the  ambulacral  plates  are  equally  characteristic  of  the  Echinidse. 
Mr.  Darwin  also  has  examined  this  fossil  and  rejected  it  from  his  province  of  inquiry. 

"  Professor  Forbes  could  not  make  up  his  mind  to  describe  the  specimen,  and  ulti- 
mately it  was  returned  to  Mr.  Flower,  with  whom  it  remained  until  the  publication  of  a 
note  on  the  genus  Profo-echinus,  by  Major  Thomas  Austin,  in  the  '  Geologist'  for  18G0 
(vol.  iii,  p.  44G),  when  it  was  entrusted  to  me  for  the  purpose  of  considering  whether  it 
had  any  special  affinity  with  this  new  type,  and  for  description  in  the  same  journal. 

"  The  Proto-ecMniis  was  obtained  from  the  Carboniferous  Limestone  of  Hook  Head, 
Wexford,  and  is  but  a  fragment  of  a  single  ambulacrum,  consisting  of  three  series  of 
plates  at  the  wider  end  and  two  at  the  other  extremity,  with  apparently  a  single  terminal 

'  '  On  Echinothuria  Jloris,  a  new  and  anomalous  Echinoderm  from  the  Chalk  of  Kent.'  By  S.  P. 
Woodward,  F.G.S.  I  have  printed  tliis  paper  from  the  '  Geologist '  entire  (altering  the  references  to 
figures),  as  a  contribution  to  British  Echinology  by  my  late  esteemed  friend.  Dr.  Woodward  took  so 
warm  an  interest  in  my  work,  and  aiTorded  me  such  valuable  assistance,  by  the  loan  of  specimens  for 
fig;uring,  that  it  affords  me  very  great  pleasure  to  acknowledge  here  his  uniform  kindness,  and  connect 
his  name  with  a  Monograph  to  which  be  contributed  important  aid. 


126  ECHINOTHURJA 

plate.     Each  plate  is  perforated  by  a  pair  of  pores.     It  differs  from  EcJiinofhuria  in 
every  particular. 

"  The  question  presented  to  me  by  Mr.  Flower's  fossil  was,  whether  to  consider  it  part 
of  the  envelope  of  a  new  kind  of  Hohfhurla,  or  whether  it  might  be  no  more  than  a  fragment 
of  the  oral  disc  of  some  great  unknown  Echinus.     Portions  of  tlie  imbricating  scaly 
armour  of  a  Psolus  had  been  met  with  when  examining  the  fossils  of  the  Boidder  Clay 
collected  by  Mr.  J.  Richmond,  of  Rothsay ;  but  in  Psolus,  while  the  greater  part  of  the 
body  is  clothed  with  fish-like  scales,  the  ambulacra  are  only  developed  on  one  side,  form- 
ing  a  creepmg  disc,  the  scales  of  which  are  small  and  not  imbricated.     On  the  other  hand 
the  peristome  of  the  largest  known  Echinite  from  the  Chalk  is  less  than  an  inch  in 
diameter;  and  the  largest  recent  Sea-urchin  in  the  lAIuseum  has  an  oral  disc  not  more 
than  two  inches  wide,  whereas  the  fossil  is  a  segment  of  a  disc  which  must  have  been  at 
least  four  inches  across.     This  objection,  on  the  score  of  size,  was,  however,  less  felt 
because  the  Cyphosomas  and  Diademas  of  the  Chalk  have  larger  oral  and  apical  orifices' 
than  any  other  Urchins,  and  the  character  of  their  apical  disc  was  unknown,  beiug  only 
preserved  in  a  few  minute  specimens  of  C.  difficile,  from  Chute  Farm.     Mo'reover^here 
were  indications  in  the  Upper  Chalk  of  a  great  Diadema,  of  which  nothing  more  had  been 
obtained  than  scattered  plates  and   fragments  of  spines.     This  species  Is  referred  to  in 
Decade  V  of  the  '  Geological  Survey  '  (Article  "  Diadema,"  Section  C,  spines  tubular,  annu- 
lated).    Mr.  Wetherell  obtained  a  mass  of  Chalk  containing  above  one  hundred  fragments 
of  spines,  which  are  hollow,  striated  and  aimulated,  as  in  the  recent  D.  caUmaria.  "^Froni 
the  plates  mingled  with  the  spuies  we  ascertained  that  the  ambulacral  pores  i)resented 
the  usual  characters,  being  arranged  in  single  file,  and  a  little  crowded  near  the  peristome; 
but  many  of  the  plates  presented  only  their  smooth  inner  surfaces.     A  smaller  mass  of 
Chalk,  iu  Mr.  Wiltshire's  cabinet,  contains  similar  plates  and  spines,  mingled  with  a  few 
true  scales  and  minute  truncated  spines  like  those  of  Echinoflmria.     The  Diadema  spines 
were  erroneously  referred  by  Professor  E.  Forbes  to  the  genus  Micraster  (Decade  III,  pi.  10 
fig.  15  ;  bad,  for  they  are  not  spiral).     They  are  also  figm-ed  by  Dixon,  in  his  '  Geoloo-y 
of  Sussex,'  and  described  by  Forbes  as  -  spines  of  a  Cidaris.''    Diademas  possessing  spints 
of  this  character  are  known  to  occur  in  the  Upper  Cretaceous  strata  of  France;  and 
Dr.  Wright  has  lately  obtained  a  small  specimen  from  the  Chloritic  Marls  of  Dorsetshire. 
In  these  the  apical  disc  is  quite  small. 

"  A  more  serious  difficulty,  in  comparing  Mr.  Flower's  fossil  with  the  oral  disc  of  any 
Echinite,  was  presented  by  the  arrangement  of  the  plates  ;  in  the  recent  Echinidge  .... 
they  are  all  directed  towards  the  dental  orifice,  but  here  the  alternate  series  take  opposite 
'  dips,'  the  ambulacral  plates  overlapping  one  way  and  the  others  in  a  contrary  direction. 

"Last  year,  while  I  was  still  hesitating  about  the  publication  of  Mr.  Flower's  fossil  a 
second  specimen  was  obtained  from  Charlton,  in  Kent,  by  the  Rev.  N.  Glass,  wlio  lias 

cleared  it  from  the  matrix  with  great  skill  and  patience At  first  sight  this' specimen 

would  seem  to  solve  the  problem,  by  supplying  the  peristome  and  lantern  of  the  same 


FROM  THE  WHITE  CHALK.  127 

great  Cyphosoma  or  Biadema,  of  which  Mr.  Flower's  specimen  might  be  the  apex  or 
periproct.  But  a  closer  examination  confirms  the  objections  ab-eady  stated,  and  gives 
increasing  probabihty  to  the  other  conjecture  (if,  indeed,  it  does  not  compel  us  to  adopt 
it),  however  difficult  it  may  be  to  realise  the  notion  of  an  Echinite  having  no  proper 
'  test,'  and  clothed  entirely  with  imbricating  scales  like  those  of  the  peristome  of  Cidaris. 

"In  Mr.  Flower's  specimen  the  imperforate  plates  imbricate  towards  the  centre  (or  apex), 
where  the  smaller  ends  of  the  several  series  converge.  In  Mr.  Glass's  specimen  they  slope 
away  from  the  centre  (or  mouth),  that  is,  also  towards  the  apex.  The  perforated  or  ambulacral 
plates,  which  overlap  one  another  outwardly  {i.  e.  downwards)  in  specimen,  fig.  3  a,  are  seen 
sloping  towards  the  dental  cone  and  reclining  upon  it.  The  portion  of  an  ambulacrum,  fig. 
5  a,  consists  of  four  plates,  diminishing  in  size  from  c  to  a,  in  a  line  not  accurately  directed 
towards  the  centre.  This  portion  exhibits  the  interior  surface  of  the  plates,  known  by  their 
curved  surfaces,  destitute  of  ornamental  granules ;  it  is  not,  however,  the  oral  end  of  one  of 
the  segments  turned  over,  a  thing  scarcely  possible  to  happen,  for  in  that  case  the  dip  of 
the  plates  would  be  reversed ;  but  it  must  be  the  opposite  (or  apical)  extremity  of  a  series 
folded  back  upon  its  origin,  and  exposed  to  view  by  the  damage  which  the  surface  of  the 
specimen  has  sustained.  From  this  circumstance  it  seems  probable  that  the  whole  fossil, 
when  complete,  was  not  elongated,  nor  even  spherical,  but  somewhat  depressed  in  a  ver- 
tical direction,  though  doubtless  admitting  of  a  moderate  amount  of  flexure.  At  the  last 
hour,  after  making  the  drawing,  I  ventured  to  clear  away  the  chalk  from  the  side  of  Mr. 
Glass's  fossil,  near  where  an  ambulacral  segment  is  seen  to  curve  as  if  it  might  be  con- 
tinued round  to  the  other  surface.  This  attempt  was  successful,  for  the  ambulacrum 
and  also  the  adjacent  inter-ambulacral  segment  were  found  continuous,  though  crowded 
and  displaced  at  the  turning,  falling  again  into  regular  order,  and  diminishing  in  size, 
though  not  so  nearly  complete  as  in  Mr.  Flower's  example. 

"  After  this  apparently  conclusive  demonstration,  it  appears  desirable  to  give  a  name  to 
the  fossil,  and  to  attempt  a  short  description,  although  its  rank  and  affinities  are  to  us 
still  matter  of  conjecture.  At  present  it  is  one  of  those  anomalous  organizations  which 
Milne-Edwards  compares  to  solitary  stars,  belonging  to  no  constellation  in  particular. 
The  disciples  of  Von  Baer  may  regard  it  as  a  '  generalised  form'  of  Echinoderm,  coming, 
however,  rather  late  in  the  geological  day.  The  publication  of  it  should  be  acceptable 
to  those  who  base  their  hopes  on  the  '  imperfection  of  the  geological  record,'  as  it  seems 
to  indicate  the  former  existence  of  a  family  or  tribe  of  creatures  whose  full  history  must 
ever  remain  unknown." 

Locality  and  Stratiyrajjhical  Position. — Collected  from  the  Upper  Chalk  of  Higham, 
near  Rochester.  The  fine  specimens  in  the  Rev.  T.  Wiltshire's  cabinet  were  obtained 
from  the  Upper  Chalk  at  Gravesend  and  Charlton. 


128  CYPHOSOMA 


Genus — Cyphosoma,  Agassiz,  1840. 

Cyphosoma,  Agassiz,  1840. 
Phymosoma,  Haime,  1853. 
—  Desor,  1858. 

Cyphosoma,  Cotteau,  1863. 

Test  moderate  in  size,  circular  or  subpentagonal,  slightly  inflated  at  the  sides. 
Poriferous  zones  well  developed  and  undulated,  composed  of  simple  pores  that  in 
general  are  unigeminal  throughout,  and  sometimes  are  bigeminal  on  the  upper  surface, 
and  crowded  a  little  together  around  the  peristome.  The  poriferous  plates  are  un- 
equal and  irregular  in  their  mode  of  arrangement.  The  primary  tubercles  are  nearly 
equal  in  size  in  both  areas,  the  areolae  are  well  developed,  and  sometimes  marked  with 
radiated  striations ;  the  bosses  are  prominent,  and  have  their  summits  sharply  crenu- 
lated ;  the  mammillon  is  large,  prominent,  and  imperforate,  and  the  general  facies  of  the 
test  shows  a  regular,  and  uniform  development  of  all  its  several  elements.  The  mouth- 
opening  is  large,  the  peristome  slightly  incised,  and  the  oral  lobes  nearly  equal.  The 
discal  opening  is  large  and  pentagonal,  one  angle  of  which  extended  far  into  the  single 
inter-ambulacrum ;  the  elements  of  the  disc  were  feebly  united,  as  they  are  absent  in  all 
the  specimens  that  have  hitherto  been  collected. 

The  spines  are  long,  solid,  subcylindrical,  aciculate,  or  spatuliform ;  sometimes  they 
are  straight  and  lanceolate,  or  bent,  ramiform,  or  spoon-shaped ;  all  these  varieties  are 
figured  in  Pis.  XXIV  and  XXVI.  The  stem  is  smooth  and  marked  with  fine  longi- 
tudinal striae,  the  milled  ring  is  prominent,  the  head  distinct,  and  the  rim  of  the  aceta- 
bulum crenulated. 

The  genus  Cyphosoma  is  distinguished  from  all  others  by  its  prominent  tubercles 
with  crenulated  bosses,  and  imperforate  mammillons  ;  in  the  structure  of  these  it  resembles 
lEicMnocyphus  and  Tenmopleurus,  but  is  readily  distinguished  from  these  by  the  absence  of 
the  angular  and  sutural  impressions  which  impart  so  mai'ked  a  character  to  their  tests. 

M.  Desor  has  separated  into  the  genus  Coptosonia  all  those  Cyphosomata  from  the 
Nummulitic  formation  (Tertiary)  with  much  undulated  poriferous  zones,  tubercles  with 
very  large  mammillons,  and  having  the  plate-sutures  of  the  areas  deeply  incised ;  thus 
leaving  the  typical  Cyphosomata  as  true  Cretaceous  fossils,  which  first  appear  in  the 
Neocomian  beds,  and  attain  their  maximum  development  in  the  upper  stage  of  the 
White  Chalk. 

The  Cretaceous  rocks  of  Prance  are  very  rich  in  species  of  Cyphosoma,  of  which  a 
very  small  proportion  have  hitherto  been  found  in  the  British  islands. 


FROM  THE  LOWER  CHALK. 


129 


A. — Species  from  the  Lower  Chalk. 
Cyphosoma  granulosum,  Goldfuss,  sp.,  1826.     PI.  XXHL  figs.  2  a,  b,  c,  d. 


CiDARITES  GRANULOSUS, 
DiADEMA   GRANULOSUM, 


Echinus  Milleri, 

Echinus  granulosus, 


Goldfuss.     Petrefact.  Germanise,  pi.  xl,  fig.  7,  p.  122,  1826. 
Agassis.     Prod.,  Mem.  Soc.  des  Sc.  Nat.  de  Neufchatel,  t.  i, 

p.  189,  1836. 
Besmoulins  (pars).      Etudes   sur  les  Echinides,  p.  294, 

No.  68,  1837. 
Bujardin.      In   Lamarck's   Anim.  sans  Vertebres,  2e  ed., 
t.  iii,  p.  372,  1840. 
CiDABiTES  GRANULOSUM,        Geinitz.     Charakt.  der  Schict.  und  Petref.,  p.  90,  1842. 
DiAPEMA  —  Moms  (pars).     Catalogue  of  British  Fossils,  p.  51,  1843. 

Cyphosoma        —  Beuss.     Verstein.  der  Bohm.  Kreideform.,  p.  58,  1846. 

—  Milleri,  Agassi:  et  Desor  (pars).      Catalogue  rais.  des  Echinid., 

p.  351,  1848. 

—  —  Bronn.     Index  Palaeontologicus,  p.  381,  1848. 

—  —  B'Orbigny.     Prod.  Pal.  strat.,  t.  ii,  p.  273,  Et.  22,  1850. 

—  —  Bronn.    Lethsea  Geognost.,  Kreide-gebirges,pl.xxix,  p.  186, 

1851. 

—  KoNiGi,  Forbes.     In  Morris's  Catalogue  of  British  Fossils,  2nd  ed., 

p.  75,  1854. 
Phymosoma  GRANULOSUM,     Besor.     Synops.  des  Echinid.  foss.,  p.  87,  1856. 
Cyphosoma  —  Woodward.     Mem.  Geol.  Surv.,  Dec.  V,  p.  1,  1857. 

Phymosoma  —  HupL     Hist.  Nat.  Echinod.,  p.  508, 1862. 

Cyphosoma  —  Cotteau.      Pal.    rran9aise,   Ter.    Cretac^,  t.  vii,    p.  685, 

pi.  1169,  IS65. 

Test  large,  circular,  depressed,  convex  on  the  upper  surface,  inflated  at  the  sides,  and 
flattened  below ;  poriferous  zones  wide  and  straight  in  the  upper  third,  narrow  and  undu- 
lated at  the  ambitus  and  base ;  pores  largely  bigeminal  in  the  wide  upper  third,  and 
unigeminal  in  the  rest  of  the  zones ;  ambulacra  narrow  above,  wide  below,  with  two  rows 
of  large  tubercles,  twelve  in  each ;  inter-ambulacra  with  two  rows  of  primary  tubercles  in 
tlie  middle  of  the  area,  secondary  tubercles  wanting  in  young  specimens,  and  only  slightly 
developed  in  the  largest  tests ;  miliary  zone  wide,  depressed,  and  naked  above,  narrow 
and  granular  below ;  mouth-opening  small  and  circular ;  peristome  with  shallow  entailles  ; 
discal  opening  large,  and  widely  pentagonal. 

Dimensions. — Height  eight  tenths  of  an  inch  ;  transverse  diameter  one  inch  and  eight 
tenths. 

Description. — This  Urchin  resembles  C.  Koni^i  in  so  many  points  of  structure,  the 
absence  or  rudimentary  condition  of  the  secondary  tubercles  excepted,  that  it  may  pro- 
bably be  only  a  variety  of  that  species.     It  has,  however,  been  treated  by  different  sys- 

17 


130  CYPHOSOMA 

tematic  authors  as  specifically  distinct ;  and  in  deference  to  their  opinion,  rather  than  in 
accordance  with  my  own  convictions,  I  have  devoted  this  article  to  its  description. 

The  test  large  and  circular,  inflated  at  the  ambitus,  convex  above,  and  flat  below 
(PI.  XXIII,  figs.  2  a,  h,  c). 

The  ambulacral  areas  are  enlarged  at  the  ambitus,  moderately  wide  at  the  base,  and 
very  narrow  in  the  upper  part ;  by  reason  of  the  increased  development  of  the  poriferous 
zones  in  this  region,  from  the  ambitus  to  the  peristome,  the  tubercles  are  as  large  as 
those  in  the  inter-ambulacra,  but  in  the  upper  third  of  the  area  they  diminish  rapidly 
in  size,  and  on  the  four  or  five  coronal  plates  they  are  quite  rudimentary  (PI.  XXIII, 
fig.  2  a).  The  pores  are  arranged  in  oblique  pairs,  and  are  bigeminal  from  the  ambitus 
to  the  summit  (PI.  XXIII,  fig.  2  c,d),  and  unigeminal  from  the  ambitus  to  the  peristome, 
the  zones  forming  a  series  of  crescents  around  the  areolae  of  the  ambulacral  tubercles. 

The  inter-ambulacral  areas  have  two  rows  of  primary  tubercles,  twelve  to  thirteen  in 
each  row,  which  vary  gradually  in  size  from  the  ambitus  to  both  apertures ;  they  are  sur- 
rounded by  well-developed  areolae,  confluent  at  the  upper  and  lower  borders,  and  surrounded 
by  granules  at  the  sides.  The  secondary  tubercles  are  irregular,  very  small,  and  limited 
to  the  under  surface  (fig.  2  6).  On  one  or  two  plates  above  the  ambitus  there  are  only 
one  or  two  solitary  tubercles,  which  are,  however,  inconstant  in  different  specimens  (fig.  2  d). 
The  miHary  zone  is  narrow  and  granular  at  the  ambitus,  and  wide,  depressed,  and  naked 
on  the  upper  surface ;  the  granules  are  unequal,  of  different  sizes,  and  placed  in  semicii'- 
cular  groups  around  the  lateral  parts  of  the  areolae.  Many  of  the  granules  are  large  and 
mammillated,  and  are  nearly  as  large  as  the  row  of  secondary  tubercles,  the  small  granules 
being  compactly  fitted  in  between  them.  The  coronal  plates  are  marked  by  slight  sutural 
impressions,  which  become  more  apparent  in  consequence  of  the  nudity  of  the  depressed 
upper  surface  of  the  areas. 

The  discal  opening  is  very  large,  pentagonal,  and  angular ;  and  the  single  posterior 
ovarial  plate  is  projected  far  into  the  area  (fig.  2  a).  The  mouth-opening  is  moderate  in 
diameter  (fig.  2  b) ;  the  peristome  is  circular,  and  divided  into  ten  unequal  lobes  by  shght 
incisions  with  reflexed  borders. 

Jffinities  and  Differences. — This  species  differs  from  the  typical  forms  of  Cyphomma 
Koniffi  in  the  absence  of  a  regular  series  of  secondary  tubercles  above  the  ambitus ;  but 
in  the  general  character  of  the  test  and  in  most  of  its  details  it  has  close  affinities  with 
that  species.  Whether  the  spines  of  this  Urchin  exhibit  any  difference  from  those  attached 
to  the  typical  form  of  C.  Konitji  (PI.  XXIV,  fig.  1)  remains  to  be  determined  by  those  who 
may  be  fortunate  enough  to  discover  a  specimen  with  the  spines  adherent  to  the  test. 

Locality  and  StratigrapUcal  Position. — This  Urchin  is  found  in  the  Lower  Chalk  of 
Kent  and  Sussex.  The  specimen  figured  in  PI.  XXIII,  belonging  to  the  British  Museum, 
was  collected  near  Lewes. 

Foreign  Localities. — Houguemarre(Eure),Orglande(Manche),  from  the  Etage  Senonien, 
where  it  is  rare  (M.  Cotteau) ;  the  type  of  Goldfuss's  figure  was  collected  from  the  Chalk 
of  Westphalia. 


FROM  THE  WHITE  CHALK. 


131 


B. — Species  from  the  Upper  Chalk. 

Cyphosoma    Konigi,    MantelL     PI.  XXIII,   figs.   1,2;   PI.   XXIV,    figs.    1—7;    PL 
XXV,  fig.  3;  PI.  XXVI,  fig.  1. 


ECHINITE. 
CiDAEIS  KoNIGr, 

Echinus  Milleri, 

cldarites  variolaris, 

Echinus  Konigi, 
ClDARITES  Konigi, 
Echinus  Konigi, 

MlLLEEI, 


DiADEMA  Konigi, 
Cyphosoma  Milleri, 
diadema  granulosum, 
Cyphosoma  Milleri, 

—  ornatissimum, 

—  Milleri, 

—  MAGNinCUM, 

DiADEMA  Konigi, 
Cyphosoma  Milleri, 

—  ornatissimum, 

—  Milleri, 

—  variolabis. 
Echinus  Konigi, 
Cyphosoma  Konigi, 

ornatissimum, 

Phymosoma  Konigii, 
Cyphosoma  Konigi, 

ornatissimum, 


Parkinson.     Organic  Remains,  vol.  iii,  pi.  i,  fig.  10,  1811. 

MantelL     Geology  of  Susse.x,  p.  180,  1822. 

Besmarest.      Oursins  fossiles.  Diet.  So.   Nat.,  t.  xx.xvii, 

p.  101,  1825. 
Goldfuss.     Petref.   Germaniee,   p.   123,  pi.  xl,  figs.   9  a,  b, 

1826. 
Fleming.     British  Animals,  p.  479,  1828. 
Brongniart.     Tableau  des  Terrains,  p.  405,  1829. 
Woodward.      Synopt.  Tab.  of  Brit.  Organ.  Rem.,  p.  6,1830. 
Be  Blainville.   Zoophytes,  Die.  Sc.  Nat.,  t.  Ix,  p.  210,  1830. 
De  Blainville.     Ibid. 
Agassiz.     Prod.,  Mem.   Soc.  Sc.  Nat.  de  Neufchatel,  t.  i, 

p.  190,  1836. 
Desmoulins.      fitudes    sur    les    Echinides   foss.,   p.  294, 

No.  68,  1837. 
Besmoulins  (pars).     Ibid.,  p.  312,  No.  10,  1837. 
Agassiz.     Catal.  Syst.  Ectyp.,  p.  11,  1840. 
Morris.     Catalogue  of  British  Fossils,  p.  51,  1843. 
Agassiz   et    Besor  (pars).      Catal.   rais.    des    fichinides, 

p.  351,  1846. 
Agassiz  et  Desor.     Ibid.,  p.  352,  1846. 
Graves.    EssaiTopogr.  Ge'ognost.  Dep.  I'Oise,  p.  688,  1847. 
Graves.     Ibid. 

Bronn.     Index  Paleeontologicus,  p.  418,  1848. 
Bronn  (pars).     Ibid.,  p.  381,  I84S. 
B'Orbigny.     Prodrom.  de  Pal  strat.,  t.  ii,  p.  273,  1850. 
B'Orbigny.     Ibid.,  t.  ii,  p.  273,  1850. 
Forbes.      In   Dixon's  Geol.   of   Sussex,  pi.  xxv,  figs.  17, 

26,  27, 1850. 
Forbes.     Ibid.,  pi.  xxv,  fig.  29,  1850. 
B^Archiac.     Hist.  desProgr.  de  la  Geol.,  t.  iv,  p.  20,  1851. 
Forbes.     Morris,  British  Fossils,  2nd  ed.,  p.  75,  1851. 
Forbes.     Ibid. 

Besor.     Synopsis  des  Echinides  fossiles,  p.  86,  1856. 
Pictet.      Traite  de  Pal6ontologie,  2e  ed.,    t.  iii,  p.  243, 

1857. 
Pictet.     Ibid. 


132  •  CYPHOSOMA. 

Cyphosoma  Konigi,  Woodward.     Mem.   Geol.    Surv.,    Decade  V,   Appendix, 

1857. 
Phymosoma       —  Dujardin  et  Hupe.     Hist.  Nat.  des  Zooph.,  p.  508,  1862. 

Cyphosoma       —  Woodward.     "  On  Konig's  Sea-urchin,"  Geologist,  vol.  v, 

p.  41,  1862. 
—  —  Cotteau.     Pale'ontologie  Fran9aise,  t.  vii,  p.  678,  pi.  1167, 

1168,  1863. 

Test  large,  subcircular,  depressed,  convex  on  the  upper  surface,  inflated  at  the  sides, 
almost  flat  on  the  under  surface ;  poriferous  zones  wide  and  straight  in  the  itpper  third, 
narrow  and  imdulated  at  the  ambitus  and  base ;  pores  bigeminal  in  the  upper  thuxl,  uni- 
geminal  in  the  lower  two  thirds  of  the  zone ;  ambulacra  narrow  above,  wider  below,  with 
two  rows  of  large  tubercles,  tAvelve  in  each ;  iuter-arabulacra  with  two  regular  rows 
of  primary  tubercles  in  the  middle,  and  two  rows  of  secondary  tubercles,  irregular  in  size 
and  distribution,  on  the  zonal  sides  of  the  area ;  miliary  zone  wide,  naked,  and  depressed 
above,  narrow  and  granular  below ;  mouth-opening  small,  peristome  circular,  lobes  nearly 
equal ;  discal  opening  large,  pentagonal ;  spines  long,  subcylindrical ;  upper  third  of 
the  stem  aciculate,  spatulate,  straight  or  bent ;  lower  third  sculptured  with  fine  longitu- 
dinal lines. 

Dimensions. — Height  seven  tenths  of  an  inch  ;  transverse  diameter  two  inches. 

Description. — This  is  one  of  the  largest,  most  beautiful,  and  typical  of  our  British 
Cyphosoma;  it  was  well  figured  by  Parkinson,  1811,  in  his  'Organic  Remains,'  as  "an 
Echinite  from  Kent  with  its  spine ;"  he  gave  no  description  of  the  specimen,  and  it  was 
reserved  for  Dr.  Mantell,  1823,  to  give  it  a  specific  place  among  our  Cretaceous 
Urchins. 

The  long  list  of  synonyms  prefixed  to  this  article  exhibits  the  historical  phases  through 
which  it  has  passed,  and  the  numerous  admirable  and  accurate  di-awings  with  which  our 
excellent  friend  Mr.  C.  R.  Bone  has  enriched  our  Monograph  will  make  the  determination 
of  Cyphosoma  Konigi  a  matter  of  ease  and  certainty  to  all  future  observers. 

The  specimen  figured  PI.  XXIII,  figs.  1  a — g,  belongs  to  the  British  Museum.  The 
large  test  is  subcircidar,  slightly  convex  above,  inflated  at  the  sides,  and  flattened  below 
(fig.  1  c) ;  the  sm-face  is  highly  ornamented,  the  tubercles  are  nearly  all  of  the  same  size 
and  regular  in  their  disposition,  and  the  granules  are  large  and  conspicuous  at  the 
base. 

The  ambulacral  areas  are  narrow  above,  wide  at  the  ambitus,  and  contracted  at  the 
base;  they  possess  two  rows  of  tubercles,  12  or  13  in  each  row;  those  at  the  ambitus 
are  very  large,  and  nearly  equal  in  size  the  inter-ambulacral  tubercles ;  on  the  upper  third 
of  the  area  they  diminish  rapidly  in  magnitude,  and  from  the  ambitus  to  the  peristome 
are  much  larger. 

At  the  ambitus  the  areolae  are  wide  and  confluent,  but  on  the  upper  surface  they  are 
narrow  and  separated  only  by  a  line  of  granules  ;  the  zone  which  divides  the  two  series  is 


FROM  THE  WHITE  CHALK.  133 

contracted,  and  provided  with  two  rows  of  granules  closely  set  together,  unequal  in  size 
some  of  them  being  mammillated  at  the  angles  of  the  plates. 

The  poriferous  zones  are  narrow  and  undulated  at  the  base  and  ambitus,  and  wide  and 
straight  at  the  upper  surface ;  the  pores  are  small,  and  unigeminal  from  the  peristome  to 
the  ambitus  (fig.  1  e),  and  distinctly  bigeminal  on  more  than  the  upper  third  of  the 
zones  (fig.  1  d) ;  near  the  peristome  the  pairs  are  doubled  (fig.  1  g). 

The  inter-ambulacral  areas  are  about  one  third  wider  than  the  ambulacral,  and  furnished 
with  primary  and  secondary  tubercles ;  the  primary  series  consists  of  two  rows,  twelve  in 
each,  occupying  the  centre  of  the  plates ;  the  tubercles  are  smaller  on  the  upper  than  on 
the  lower  third  of  the  area ;  the  secondary  tubercles  are  large  and  unequal  in  size  ;  they 
form  a  series  between  the  poriferous  zones  and  primary  tubercles,  some  of  which  they 
resemble  in  magnitude,  especially  those  extending  from  the  ambitus  to  the  coronal  plates ; 
between  the  ambitus  and  peristome  they  are  much  smaller,  and  in  many  specimens  are 
not  more  developed  than  large  granules  on  mammillated  eminences. 

The  miliary  zone  is  very  wide,  naked,  and  depressed  at  the  upper  surface, 
becoming  gradually  narrower  at  the  ambitus,  and  much  contracted  at  the  base;  the  granules, 
unequal  in  size,  are  fine,  abundant,  set  closely  together,  and  arranged  in  semicircles 
around  the  primary  and  secondary  tubercles  ;  some  of  the  granules,  much  larger  than  the 
others,  are  set  on  mammillated  eminences,  and  may  easily  be  mistaken  for  the  small 
secondary  tubercles  placed  near  them  ;  this  mnigling  together  of  small  tubercles  and  large 
mammillated  granules  imparts  a  highly  ornamented  character  to  the  infra- marginal  region 
of  this  species. 

Discal  opening  large,  pentagonal,  and  subangular,  the  elements  wanting  in  all  the 
specimens  hitherto  found.  Mouth-opening  small,  circular,  the  peristome  feebly  incised, 
the  border  reflected,  the  entailles  having  the  border  elevated  and  opening  upwards.        , 

The  spines  exhibit  some  remarkable  variations  from  the  typical  form  of  structure. 
Some  of  the  most  curious  of  these  I  have  figured  in  Pis.  XXIV  and  XXVI.  The 
typical  spines,  as  seen  in  those  in  situ  in  the  specimen  belonging  the  British  Museum 
(Pi.  XXIV,  fig.  a),  are  elongated,  subcylindrical,  and  sometimes  aciculate  at  the  summit 
(fig.  1  d,  and  fig.  3  ci),  or  spatuliforra  with  carinae,  as  PI.  XXIV,  fig.  1  c,  or  spoon- 
shaped,  as  PI.  XXVI,  figs.  1  a,  b,  the  lower  part  or  coUerette  being  long  and  distinct, 
and  covered  with  fine  longitudinal  lines  (PI.  XXIV,  fig.  3  b),  much  stronger  than  those 
observed  on  the  stem ;  the  head  is  well  developed,  the  milled  ring  very  prominent,  flat, 
and  deeply  striated,  and  the  rim  of  the  acetabulum  finely  crenulated  (PI.  XXVI,  figs.  1 
a,  c,  figs.  2,  4,  6),  with  other  varieties  of  spines  figured  in  this  plate. 

The  test  of  this  Urchin  presents  many  variations  of  form  from  the  typical  shape  seen 
in  the  specimen  figured  in  PI.  XXIII,  fig.  1  a,  h,  and  considered  to  be  its  normal  form. 
In  PI.  XXIV,  fig.  7,  I  have  figured  a  remarkable  monstrosity  of  this  species  from 
the  British  Museum  Collection ;  it  is  inversely  conical,  like  Pseudodiadema  tumidmn ; 
measures  three  quarters  of  an  inch  in  height,  and  is  one  inch  and  one  third  in  diameter 


134  CYPHOSOMA 

above,  contracting  below  down  to  the  oral  opening,  which,  at  first  sight,  appears  to  be  the 
summit  of  the  test.  In  PL  XXII,  figs.  5  a,  h,  c,  I  have  given  drawings  of  a  young  test 
from  the  National  Collection. 

Affinities  and  Differences. — This  species  forms  one  of  the  most  typical  forms  of  the 
genus  Cyphosoma,  well  characterised  by  its  large  size,  round  and  inflated  at  the 
ambitus,  highly  ornamented  at  the  base,  and  having  the  poriferous  pores  distinctly 
bigeminal  in  all  the  upper  part  of  the  zones ;  the  secondary  tubercles  are  large  above  the 
ambitus  and  small  at  the  base ;  the  spines  are  strong,  elongated,  and  furnished  with  a 
striated  collar,  having  the  summit  sometimes  flattened  and  carinatedj  or  expanded  and 
spatulate,  as  seen  in  the  different  figm^es. 

The  nearest  affinities  of  C.  Konigi  are  with  C.  granulosum,  from  which  it  differs  in 
having  large  secondary  tubercles  above  the  ambitus  and  a  more  ornamented  test  at  the 
base.  In  size  and  height,  and  in  the  disposition  of  its  tubercles  on  the  upper  surface,  as 
well  as  in  the  bigeminal  arrangement  of  the  pores  in  the  upper  part  of  the  zones,  it  much 
resembles  C.  magnificmn,  Agass.,  from  the  Etage  Senonien  inferienre  of  the  south-west 
of  France. 

Locality  and  Stratigraphical  Position. — C.  Konigi  is  found  in  fine  preservation  in  the 
Upper  Chalk  of  Kent,  Sussex,  Norfolk,  Wiltshire,  and  Yorkshire.  In  France  it  is  col- 
lected in  the  Etage  Senonian  at  Thuison  (Somme) ;  Tartigny  (Oise) ;  Vernonnet,  La 
Villette,  Hougouemarre  (Eure) ;  where  it  is  rare.  It  is  likewise  found  at  Riigen,  and 
Csesfeld,  near  Dusseldorf. 


Cyphosoma  corollare,  Klein.     PI.  XXVI,  figs.  7,  8,  9,  10. 

EcHiNiTES  OEBICULATUS,  Xwier.     Ilist.  Animal.  Anglise,  p.  220,  pl.vii,  fig.  19,  1678. 
CiDARTS  coKOLLARis,         Klein.      Natur.  Dispos.  Echinoderm.,  pi.  viii,  fig.  c,  p.  20, 

1734. 

—  —  Baier.     Oryctographia  Norica,  p.  70,  pi.  iii,  fig.  36,  1759. 

—  —  Leske.     Klein,  Nat.  Dispos.    Echinoderm.,  p.  138,  pi.  viii, 

fig.  c,  1778. 

—  coRONAiiis,  Gmelin.     Linne's  System.  Natur.,  p.  3177,  1788. 
Echinus  saxatilis,           Parkinson.     Organic  Remains,  pi.  iii,  fig.  1,  1811. 
CiDARis  COKOLLARIS,         Parkinson.     Ibid.,  pi.  i,  fig.  7,  1811. 

—  SAXATILIS,  Mantell.     Geology  of  Sussex,  p.  ISO,  1822. 

—  coROLLARis,         Mantell.     Ibid.,  p.  181,  1822. 

EcHiNDS  SAXATILIS,  Fleming.     History  of  British  Animals,  p.  479,  1828. 

—  —  Brongniart.     Tableau  des  Terrains,  p.  40.5,  1829. 

—  —  JT'oodwarJ.     Synop.  Table  of  Brit.  Org.  Remains,  p.  6,  1830. 

—  —  I)e  Blainville.     Zoophytes,  Diet,  des  Sc.  Nat.,  t.  Is,  p.  210, 

1830. 
CiDARis  COROLLARIS,         Agassiz.     Prodrome  des  Radiaires,  p.  188,  1836. 
Echinus  coeollaris,        Besmoulins.     Etudes  sur  les  Echinides,  p.  298,  1837. 


FROM  THE  UPPER  CHALK.  135 

CiDARis  cOEOLLAKis,         Morris.     Catalogue  of  British  Fossils,  p.  49,  1843. 

—  SAXATiLis,  Morris.     Ibid.,  p.  50,  1843. 

CypHOSOMA  COKOLLAKE,    Agassiz  et  Desor.     Catal.  Rais.  des  Echinides,  p.  351, 1846. 
CiDARis  coEOLLARis,  Bronn.     Index  Palseontologicus,  p.  298,  1848. 

—  SAXATILIS,  Bronn.     Ibid.,  p.  300,  1848. 

Cyphosoma  corollare,  TfOrUgny.     Prodrome,  t.  ii,  p.  273,  Et.  22,  1850. 

—  —  Forbes.     In  Dixon's  Geol.  of  Sussex,  p.  340,  1850. 

—  —  Forbes.     In  Morris's  Catalogue  of  Brit.  Foss.,  p.  75,  1850. 
Phymosoma        —  Desor.     Synop.  des  Echinides  fossiles,  p.  88,  1856. 
Cyphosoma  saxatile,  Desor.     Ibid.,  p.  87,  1856. 

—  COROLLARE,      Pictet.     Paleontologie,  2e  ed.,  t.  iii,  p.  243,  1857. 

—  —  Woodward.     Mem.  Geol.  Surv.,  Decade  V,  p.  2,  1858. 

—  —  Leymerie  et  Raidin.     Ge'ol.  du  Depart,  de  I'Yonne,  p.  621, 

1858. 
Phymosoma  saxatile,        Diijardin  et  Hupe.     Hist,  des  Echinoderm.,  p.  508,  1862. 

—         COROLLARE,    Dvjardin  et  Hupe.     Ibid. 
Cyphosoma  perfectlm,     Cotteau  et  Triger.     Echinides  de  la  Sartlie,  p.  261,  pi.  xlii, 

figs.  13—16,  1860. 

—  —  Cotteau.     Echinides  foss.  des  Pyrenees,  p.  24,  1863. 

—  COROLLARE,      Cotteau.     Pal.  Fran^aise,  t.  vii,  p.  669,  pi.  1165,  1864. 

Test  small,  circular,  depressed ;  ambulacra  wide,  two  rows  of  tubercles,  nine  to  ten  in 
each,  gradually  diminishing  in  size  towards  the  poles ;  inter-ambulacra  moderate,  with  two 
rows  of  tubercles,  nine  in  each,  four  ambital,  large ;  areolae  defined  by  rows  of  granules ; 
miliary  zone  moderate,  granular  below,  becoming  smooth  above ;  poriferous  zones  narrow, 
undulated,  pores  unigeminal,  and  crowded  near  the  summit ;  base  concave ;  oral  opening 
small,  one  third  of  an  inch  in  diameter ;  discal  opening  large,  pentagonal,  half  an  inch 
in  diameter ;  spines  long,  slender,  spatulate,  one  fom'th  longer  than  the  diameter  of  the 
test. 

Dimensions. — Transverse  diameter  one  inch ;  height  one  third  of  an  inch  ;  in  general 
the  specimens  are  not  so  large. 

Description. — This  is  one  of  our  most  common  Cyphosomuta.  In  certain  localities  it  is 
a  small,  circular  Urchin,  rarely  exceeding  an  inch  in  diameter  and  about  three  or  four 
lines  in  height ;  it  is  convex  and  depressed  above,  and  flat  or  subconcave  below ;  the  areas 
are  nearly  equal  in  width,  the  tubercles  very  much  alike  in  form  and  size,  the  areolae  are 
encircled  with  granules,  and  the  structure  of  the  different  divisions  of  the  test  is  very 
uniform  throughout. 

The  ambulacral  areas  (PI.  XXVI,  fig.  10),  contracted  above  by  the  poriferous  zones, 
have  two  rows  of  primary  tubercles  supported  on  large  bosses,  and  arranged  in  alternate 
series  on  each  side  of  the  area ;  in  adult  specimens  there  are  nine  or  ten  tubercles  in  a 
row ;  the  areolae  are  wide,  and  a  single  row  of  graimles  (rarely  double)  separates  them 
from  each  other. 

The  poriferous  zones  are  narrow,  and  much  undulated  at  the  ambitus  and  infra-mar- 


136  CYPHOSOMA 

ginal  region ;  tlie  small  pores  are  arranged  in  oblique  pairs  at  the  sides,  and  at  the  upper 
surface  become  bigeminal;  fig.  10  shows  an  ambulacral  area  with  its  poriferous 
zones  magnified  six  diameters  ;  fig.  7  h  exhibits  the  upper  part  of  the  area  magnified  six 
times,  with  the  bigeminal  arrangement  of  the  pores  in  the  upper  part  of  the  zones. 

The  inter-ambulacral  areas  are  furnished  with  two  rows  of  tubercles  nearly  identical 
with  those  of  the  ambidacral ;  they  are,  however,  a  little  larger  than  the  latter  in  the  upper 
surface,  and  are  surrounded  by  areolae  that  are  placed  wider  apart.  The  secondary 
tubercles  are  very  small  and  unequal  in  size;  they  form  a  series  near  the  zones,  one  mam- 
millated  tubercle  rising  in  each  plate  from  the  midst  of  numerous  granules.  They  are 
most  apparent  at  the  lower  surface  and  the  ambitus,  and  are  rare  on  the  upper  surface. 

The  miliary  zone  is  wide,  naked,  and  depressed  in  the  upper  surface,  forming  at  the 
ambitus  and  lower  surface  a  zigzag  line,  Avhich  defines  the  contour  of  the  plates.  The 
granules  are  large,  and  those  surrounding  the  primary  tubercles  at  the  ambitus  send  pro- 
longations into  the  areolae,  which  impart  a  radiated  character  to  the  structure  of  these 
parts.  The  intermediate  granules  are  more  or  less  abundant,  and  form  circles  or  semi- 
circles around  the  areolae.  The  small  mouth-opening  is  lodged  in  a  concave  depression 
in  the  base.  The  peristome  is  circular,  and  divided  by  feeble  incisions,  the  lobes  of 
which  are  nearly  equal.  The  apical  disc  is  absent.  The  opening  is  large,  pentagonal, 
and  angular,  and  in  our  large  specimen  is  about  five  lines  in  diameter. 

The  spines  are  long,  slender,  and  spatulate,  one  fourth  longer  than  the  diameter  of  the 
test,  to  which  they  are  sometimes  found  adherent  and  in  situ. 

Affinities  and  Differences. —  C.  corollare  is  readily  recognised  by  its  moderate  size, 
depressed  circular  test,  sometimes  subpentagonal ;  the  pores  are  unigeminal  on  the  sides 
and  bigeminal  on  the  upper  surface,  with  small  secondary  tubercles  at  the  base  near  to  the 
zones ;  the  miliary  zone  is  nude  and  depressed  near  the  summit ;  the  mouth-opening  is  small, 
and  lodged  in  a  concave  depression.  By  these  characters  it  may  be  distinguished  from 
C.  tiara  and  young  examples  of  C.  yranidosum,  both  of  which  it  resembles  much. 

Locality  and  Stratiyraphical  Position. — This  Urchin  is  very  common  in  the  upper 
flinty  Chalk  of  Brighton,  Gravesend,  and  Woolwich.  In  France  M.  Cotteau  enumerates 
the  following  localities  in  which  it  is  rarely  found  in  the  Etage  Senonien  : — Senneville, 
Saint-Pierre  en  Port  (Craie  superieure,  M.  Hebert) ;  Seine  Inferiem'e,  La  Herelle  (Oise) ; 
Pinterville  (Eure)  ;  Villeneuve-sur-Yonne  (Yonne) ;  Meudon  (Seine-et-Oise)  ;  Sarlat 
(Dordogne) ;  Tercis  (Landes). 

History. — The  history  of  this  species,  one  of  the  oldest  Cyphosomas,  is  very  difficult 
to  trace,  as  our  table  of  synonyms  has  already  exposed.  Lister  and  Klein  have  both 
figured  it,  and  Parkinson  has  given  a  very  good  figure  of  it  under  the  name  of  Echinites 
saxatilis  in  his  'Organic  Remains.'  Klein's  name,  however,  has  the  priority,  and 
therefore  is  retained. 


THE 


PALiEONTOGRAPHICAL  SOCIETY. 


INSTITUTED   MDCCCXLVII. 


VOLUME  FOR  1870. 


LONDON: 

KDOCOLXXI. 


MONOGRAPH 


ON    THE 


BRITISH     FOSSIL 


ECHINODBRMATA 


THE  CRETACEOUS  FORMATIONS. 


THOMAS  WRIGHT,  M.D.,  F.R.S.  Edin.,  F.G.S.     ^  '""  ^ 

CORKESVONDING    MEMBER  OF   THE    KOYAL   SOCIETY   OF  SCIENCES  OF   LIEGE,    THE    SOCTETV   OF 

NATURAL  SCIENCES    OP  NEUFCIIATEL,   AND    SENIOR   SURGEON   TO 

THE    CHELTENHAM    HOSPITAL. 


VOLUME    FIRST. 

PART  FOURTH. 
ON  THE  DIADEMADYE  AND  SALENIHi^.. 

Pages  137—160  ;  Plates  XXX— XXXIX. 


LONDON: 

PRINTED   FOR   THE    PAL^ONTOGRAPHICAL   SOCIETY. 

1871. 


PBINTED  BY 
J.    E.    ADLAED,  BAETHOLOMEW    CLOSE. 


FROM  THE  UPPER  CHALK.  137 


Cyphosoma  MAGNiFicuM,  Affossiz,  1840.    PI.  XXV,  figs.  1,  2  a,  h,  c,  d,  e. 

Ctphosoma  MAGNii'icUM,       Affossiz.     Catal.  Syst.  Ectvp.,  p.  11,  1840. 

—  SULCATUM,  Agassiz  et  Desor.      Catal.  raison.  des  Echinides,  p.  351, 

18-16. 

—  MAGNIFICUM,       Bfotin.    Index  Palaeontol.,  p.  38 1 ,  1 848. 
Phtmosoma  —  Desor.    Synops.  des  Echinides  fo8s.,  p.  88,  1856. 

—  SULCATUM,        Desor.     Ibid.,  p.  90,  1856. 

Ctphosoma  MiDDELTONi,      Woodward.    Mem.  Geol.  Siirv.,  Decade  V,  App.,  p.  4,  1856. 

—  SULCATUM,  Pictet.     Traite  de  Paleontol.,  2eed.,  t.  iv,  p.  243,  1857. 

—  —  Cotteau  et  Triger.     Echinides  de  la  Sarthe,  pi.  44,  fig.  9, 

1860. 
PiiYMOSOMA         —  Coquand.     Synops.  des  Foss.,  Bull.  Soc.  Ge'ol.  de  France, 

t.  xvi,  p.  992,  1860. 
Phtmosoma        —  Dujardin  et  Hiipe.     Hist.  Nat.  Zooph.,  p.  508,  1862. 

Ctphosoma         —  Bourgeois.     Especes  Ter.  Cretaces,  Bull.  Soc.  Geol.  France, 

deux,  ser.,  t.  xix,  p.  674,  1862. 

—  MAGNIFICUM,       Cotteau.     Echinides  foss.  des  Pyrenees,  p.  25,  1863. 

—  —  Cotteau.    Paleontologie  Erancaise  ;  Ter.  Cretace,  t.  vii,  p. 

635,  pis.  1155-56-57,  1865. 

Test  circular,  elevated,  sides  tumid,  base  concave ;  poriferous  zones  narrow,  undulated, 
pores  unigeminal ;  primary  tubercles  of  both  areas  large  at  the  base  and  ambitus,  and 
small  on  the  upper  surface  ;  areolae  large  and  confluent  at  ambitus  and  base^  very  small 
above;  upper  third  of  inter-ambulacra  bordered  with  a  row  of  small  secondary  tubercles; 
miliary  zone  wide,  sulcated,  and  nude  above ;  mouth-opening  small,  peristome  equal- 
lobed;  discal  opening  very  large,  pentagonal,  angular,  and  elongated. 

Dimensions. — a.  Figured  specimen,  latitude  ten  lines  ;  altitude  six  lines. 

B.  Specimen  in  my  cabinet,  latitude  one  inch  ;  altitude  half  an  inch  ;  discal  opening 
(antero-posterior  diameter)  six  tenths  of  an  inch. 

Bescripfion. — This  very  rare  British  Cyphosoma  was  obtained  by  J.  Middleton,  Esq., 
from  the  Upper  Chalk,  near  Norwich,  and  placed  in  the  hands  of  the  late  Professor  Edward 
Forbes  for  description,  whose  manuscript  name  for  the  same  was  C.  Middeltoni.  Under 
this  designation  a  diagnosis  of  the  species  was  given  by  my  late  friend  Dr.  Woodward, 
in  his  valuable  appendix  to  Decade  V  of  the  '  Memoirs  of  the  Geological  Survey,'  who 
kindly  obtained  another  specimen,  to  enable  me  to  give  a  detailed  description  of  this  I'are 
British  form ;  a  careful  examination  of  this  fossil,  however,  has  satisfied  me  that  it  is 
merely  a  small  variety  of  Cyphosoma  magnijicim,  Agassiz,  and  agrees  in  all  its  specific 
characters  with  the  sulcate  variety  of  that  species. 

The  test  is  circular,  elevated,  or  moderately  depressed  on  the  upper  surface,  inflated  at 
the  sides  (PI.  XXV,  figs.  1  a  and  d)  and  concave  at  the  base  (fig.  1  c).     The  ambulacral 

18 


138  CYPHOSOMA 

areas  are  wide;  with  two  rows  of  tubercles,  which  are  large  at  the  ambitus  and  base 
and  veiy  small  on  the  upper  surface ;  the  change  from  the  large  ambital  to  the  small 
dorsal  tubercles  is  very  abrupt ;  the  areolae  of  all  the  large  tubercles  are  wide  and 
confluent,  and  those  of  the  smaller  are  surrounded  by. circlets  of  granules. 

The  poriferous  zones  are  narrow,  and  much  undulated  at  the  ambitus  and  infra-mar- 
ginal region  ;  they  are  less  sinuous  above,  where  the  pores  are  small  and  unigeminal ;  the 
spaces  between  the  pairs  of  holes  often  support  two  small  granules  (fig.  1  e). 

The  inter-ambulacral  areas  are  about  one  third  wider  than  the  arabulacral,  and  pro- 
vided with  two  rows  of  primary  tubercles,  twelve  in  each,  nearly  identical  with  those  in 
the  ambulacra;  like  them,  they  have  wide  areolae  at  the  ambitus  and  infra-marginal  region, 
and  very  small  on  the  upper  surface ;  the  transition  from  the  large  ambital  to  the  small  dorsal 
tubercles  is  likewise  well  marked  in  the  specimen  before  me  (fig.  I  a,  d).  A  row  of  small 
irregular  secondary  tubercles,  five  or  six  in  each,  occupies  the  spaces  between  the  primary 
series  and  the  poriferous  zones  (figs.  1  d,  d),  and  disappears  among  the  granules  of  this 
region.  Other  secondary  tubercles  occupy  the  wide  spaces  by  the  zones  at  the  angles  of  the 
plates  (figs.  1  c,  e,  and  figs.  2  a,  b),  and  range  in  file  with  the  small  secondary  series  on  the 
upper  surface.  The  intermediate  granules  are  large  and  abundant,  of  unequal  size,  and 
disposed  in  circles  around  the  areolae ;  these  circles  at  the  ambitus  are  incomplete  at 
their  basal  border  (fig.  1  e).  The  miliary  zone  is  large,  much  depressed  in  the  middle, 
and  nude  as  it  approaches  the  discal  opening  (fig.  1  d) ;  the  small  granules  forming  complete 
circlets  around  the  small  tubercles  of  this  region. 

The  primary  tubercles  at  the  under  surface  are  moderately  large,  and  nearly  the  same 
size  in  both  areas  (fig.  1  c,  and  fig.  2  b),  which  imparts  a  highly  ornamented  character 
to  this  region  of  the  test  and  contrasts  strongly  with  the  small  tubercles,  and  the  naked 
and  depressed  miliary  zone  on  the  upper  surface  (fig.  1  d). 

The  mouth-opening  is  small,  the  peristome  circular,  and  divided  into  nearly  equal- 
sized  lobes  by  feeble  incisicms  (fig.  1  c).  The  discal  opening  is  large,  pentagonal,  angular, 
and  elongated  in  the  antero-posterior  direction  (fig.  \  b). 

C^hosoma  vnic/nijicum,  so  rare  in  England,  is  a  very  common  species  in  the  south- 
west of  France,  Avhere  two  well-marked  varieties  are  found.  The/r*/f  type  of  the  species 
is  characterised  by  having  its  ambulacral  and  inter-ambulacral  tubercles  large  and  promi- 
nent at  the  ambitus,  becoming  gradually  smaller  on  the  upper  surface,  the  miliary  zone  wide 
and  not  depressed  in  the  middle.  In  the  second  type  the  transition  in  size  from  the  large 
ambital  to  the  small  dorsal  tubercles  is  more  abrupt,  the  upper  part  of  the  miliary  zone  is 
quite  destitute  of  granules  and  much  depressed  in  the  middle,  near  the  coronal  plates,  which 
are  marked  with  very  distinct  sutures ;  the  areolae  at  the  ambitus  are  larger  and  more  super- 
ficial, and  the  under  surface  has  a  more  ornamented  appearance.  This  variety  has  been 
described  as  C.  sulcatum,  and  is  that  to  which  our  specimen  is  referred.  It  attains  a  much 
larger  size  than  the  first  or  type  form,  as  a  specimen  collected  from  the  Chalk  of  Royan 


FROM  THE  UPPER  CHALK.  139 

(Cliarente-Inferieure)  measures  two  and  a  half  inches  in  diameter,  and  one  incli  and 
one  tenth  in  height. 

The  English  specimens  of  this  Urchin  that  have  hitherto  been  collected  are  small 
and  immature,  they  consequently  have  fewer  tubercles  in  each  row  tiiau  the  French 
specimens  possess,  and  the  poriferous  zones,  for  a  like  reason,  have  the  pores  in  single  file, 
the  bin;eminal  arrangement  being  a  character  of  more  mature  age. 

Affinities  and  Differences. — This  species  differs  so  much  from  its  English  congeners 
that  it  is  readily  distinguished  from  all  of  them  by  its  wide  anibital  areolae  and  large 
tubercles,  and  the  series  of  small  tubercles  on  the  upper  surface,  with  a  secondary  row  on 
the  zonal  side.  In  its  general  characters  C.  magnificum  resembles  C.  Archiaci  from  the 
same  stage,  but  the  latter  has  a  more  pentagonal  test,  wider  inter-ambulacral  areas, 
smaller  primaiy  tubercles,  and  four  rows  of  secondary  tubercles ;  the  base  likewise  is 
flatter,  and  the  mouth-opening  larger  and  more  superficial. 

Locality  and  Stratigraphical  Position. — The  English  specimens  have  been  found  only 
in  the  Upper  Chalk  at  Norwich,  where  they  are  extremely  rare. 

M.  Cotteau  states  that  this  species  is  common  in  the  Etage  Senonien  inf.  at  Saint- 
Pierre  de  Cheville,  Saint-Paterne,  Saint-Calais^  Marcon  (Sarthe) ;  Villers,  Villedieu  (Loir- 
et-Cher);  Saint-Christophe,  Semblangy  (Indre-et-Loire) ;  Barbezieux,  Aubeterre,  Espagnac, 
prcs  Angouleme,  Charmant,  Lavalette  (Charente) ;  Royan,  Talmont,  Saintes,  Cognac 
(Charente-Inferieure),  Saint-Georges  pros  Perigueux,  Tretissac  (Dordogne) ;  Belbeze 
(Haute- Garonne). 

History. — The  table  of  synonyms  gives  the  history  of  this  species,  which  was  unknown 
to  my  old  friend  Professor  Forbes,  who  named  the  only  specimen  he  ever  saw  after  the 
friend  who  communicated  it  for  description. 


Cyphosoma  Wetherelli,  Forbes.     PI.  XXVH,  figs.  1,  a — h. 

Cyphosoma  Wetherelli,    Forbes.     In  Morris's  Catalogue  of  British  Fossils,  2nd  ed., 

p.  7f>,  1854. 
—  —  Woodward.      Mem.   Geol.  Surv.,   Decade  V,  Supplement, 

p.  2,  1856. 

Test  circular,  inflated  at  the  sides,  depressed  at  the  summit,  and  flat  beneath ;  ambu- 
lacra wide,  two  rows  of  large  tubercles,  nine  to  ten  in  each,  gradually  diminishing  in 
size  towards  the  poles  ;  inter-ambulacra,  two  rows  of  primary  tubercles,  nine  in  each, 
with  a  small  secondary  tubercle  in  the  centre  of  the  zonal  margin  of  each  plate;  poriferous 
zones  narrow,  undulated;  pores  unigeminal  throughout;  mouth-opening  one  third  the 
diameter  of  the  test ;  discal  opening  large,  angular,  pentagonal. 

Dimensions. — Transverse  diameter  one  inch;  height  half  an  inch. 

Description. — This  Urchin  very  much  resembles  C.  corollare,  Klein,  but  was  separated 


140  CYPHOSOMA 

from  that  species  by  the  late  Professor  Edward  Forbes,  and  dedicated  to  N.  T.  Wetherell, 
Esq.,  F.G.S.,  who  presented  it  to  the  Museum  of  the  Royal  School  of  Mines.  This 
unique  typical  example,  partly  imbedded  in  flint,  was  obtained  at  Gravesend.  The  test 
is  of  moderate  size,  has  a  circular  figure,  and  is  depressed  a  little  above  and  below ;  the 
sides  are  inflated  and  the  base  is  flat ;  the  ambulacral  areas  are  wide,  with  two  rows  of 
large  tubercles  (figs.  1  c,  b),  nine  or  ten  in  each ;  the  areolae  occupy  nearly  the  entire 
width  of  the  plates,  and  are  bordered  by  a  series  of  prominent  miUary  granules,  which  are 
absent  only  on  the  zonal  sides  of  the  plates  (figs.  1  e,  g,  h)  \  the  tubercles  gradually 
diminish  from  the  ambitus  to  the  oral  (fig.  1  ]i)  and  the  discal  apertures  (fig.  1  g)  ; 
the  areolae  retain  throughout,  even  to  the  smallest  tubercles,  the  border  of  granules  special 
to  each  (figs,  g,  h). 

The  poriferous  zones  are  much  undulated,  and  form  a  series  of  crescents  around  the 
large  tubercles  (fig.  1,  d) ;  the  rows  are  narrow,  the  pores  simple  and  unigeminal  through- 
out, and  there  are  from  five  to  six  pairs  of  holes  opposite  each  of  the  large  plates 
(figs,  e,  g,  h). 

The  inter-ambulacral  areas,  a  little  wider  than  the  ambulacral,  have  two  rows  of 
primary  tubercles,  nine  in  each,  and  two  rows  of  secondary  tubercles  placed  near  the 
zones,  and  extending  from  the  peristome  to  the  ambitus  (fig.  ]  c  and  fig.  1  h).  The 
areolae  of  the  primaries  are  wide,  occupying  nearly  the  whole  surface  of  the  plates,  and 
each  is  bordered  by  a  row  of  distinct  miliary  granules  (fig.  1  e),  which  completely  separates 
the  areolae  from  each  other.  The  secondary  tubercles  are  small,  and  form  a  short  row  of 
twelve  tubercles  set  on  bosses  ;  they  occupy  a  space  between  the  zones  and  the  primary 
tubercles  (figs.  1  c,  //),  and  extend  from  the  peristome  to  the  ambitus. 

The  tubercles  of  both  areas  are  very  prominent,  and  nearly  of  the  same  size;  the 
bosses  are  large,  with  feebly  crenulated  sunmiits,  closely  embracing  the  mammillou,  which 
is  large  and  conspicuous  (figs.  1  e  and/). 

The  miliary  zone  is  narrow  at  the  ambitus,  with  two  rows  of  granules ;  on  the  upper 
surface  it  becomes  wider,  depressed,  and  nude  in  the  middle,  and  is  sparsely  supplied 
there,  and  at  the  sides,  with  very  small  granules  (fig.  1  d). 

The  mouth-opening,  small  and  circular,  is  one  third  the  diameter  of  the  test; 
the  peristome  is  divided  into  ten  nearly  equal-sized  lobes,  by  well  defined  incisions 
(«g.  Ic). 

The  discal  opening  is  directly  opposite  to,  and  of  the  same  proportional  size  as  the 
oral  aperture;  it  has  a  pentagonal  form,  and  the  single  ovarial  plate  that  extended  into 
the  single  inter-ambulacrum  protruded  farther  into  this  area  than  either  the  antero-  or 
postero-lateral  ovarials  (fig.  1  6). 

The  upper  surface  of  the  test  is  considerably  depressed,  and  the  base  is  fiat.  This 
contour  of  the  shell  is  well  shown  in  fig.  1  d. 

Ajfinities  and  Differences. — This  species  has  the  closest  affinities  with  Cyphosoma 
corollare,  of  which  it  may,  perhaps,  prove  to  be  only  a  variety.     As  it  is  at  present  a 


PROM  THE  UPPER  CHALK.  141 

uniciun,  we  wait  for  the  discovery  of  other  specimens  with  spines  before  stating  with 
confidence  its  affinitive  relations. 

Locality  and  Strati (jraphical  Position. — Poimd  imbedded  in  a  flint  nodule  at  Gravesend, 
from  the  Upper  Chalk. .  The  specimen  belongs  to  the  Museum  of  the  Royal  School  of 
Mines. 


CvPHOsoMA  SPATULIFERUM,  i^ories,1850.  PI.  XXVIII,  figs.  1«,  b,  c,  d,  e,f,g,  h;  PI.  XXIX, 

figs.  1  a,  b,  c,  d. 

Ctphosoma   SPATULIFERUM,   Forhes.     Dixon's  Geology  of  Sussex,  pi.  xxiv,  fig.   20, 

p.  340,  1850. 

—  —  Forbes.      In   Morris's   Catalogue   Brit.    Foss.,   2Qd   ed., 

p.  7.5,  1854. 

—  —  Woodward.      Mem.  Geol.  Surv.,  Decade  V,  Supplement, 

p.  2,  1856. 

Test  small,  circular,  inflated  at  the  sides,  concave  at  the  base,  and  depressed  on  the 
upper  surface ;  ambulacra  prominent,  two  rows  of  tubercles,  eight  to  ten  in  each ;  areolae 
wide,  bordered  by  granules ;  inter-ambulacra  with  two  rows  of  primary  tubercles,  nine 
in  each,  and  two  short  rows  of  secondary  tubercles ;  areolae  wide,  bordered  by  granules. 
Poriferous  zones  much  undulated  ;  pores  unigeminal ;  tubercles  of  both  areas  nearly 
ahke  in  size  and  structure.  Mouth-opening  one  third  the  diameter  of  the  test ;  discal 
aperture  peutagonal,  large  and  angular.  Spines  spatulate,  very  much  flattened,  smooth 
except  near  the  base,  where  there  are  fine  longitudinal  lines. 

Dimensions. — Height  nine  twentieths  of  an  inch ;  transverse  diameter  seven  tenths 
of  an  inch. 

Descrijjtion. — This  beautiful  little  Cyphosoma  has  a  circular  body,  with  inflated  sides 
and  small  projecting  equal-sized  tubercles ;  the  ambulacra]  areas  are  prominent,  and  have 
two  rows  of  tubercles  ;  fig.  1/  shows  one  of  these  segments  magnified  six  times ;  the  areolae 
are  wide,  and  fill  nearly  the  entire  plate  ;  the  inner  atd  upper  margins  of  each  are  bor- 
dered by  a  series  of  miliary  granules,  which  define  the  boundary  of  the  areolae,  and  entirely 
prevent  them  becoming  confluent.  The  tubercles  at  the  ambitus  are  a  little  larger,  and  they 
gradually  become  smaller  as  they  approach  the  two  apertures.  The  narrow  poriferous 
zones  are  much  undulated,  and  form  a  series  of  crescents  around  the  large  plates ;  there 
are,  in  general,  six  pairs  of  holes  opposite  each  plate,  and  they  are  entirely  unigeminal 
throughout  (fig.  1/). 

The  inter-ambulacral  areas  are  a  little  wider  than  the  ambulacral,  and  composed  of  large 
plates  (PI.  XXVIII,  fig.  1  y ;  PI.  XXIX,  fig.  1  d),  of  which  there  are  nine  in  each  column. 
The  areolae  are  wide,  and  bordered  by  a  circle  of  miliary  granules,  complete  on  five  sides 
of  the  plate,  but  absent  on  lower  margin  (PI.  XXIX,  fig.   1  d).     The  miliary  zone  is 


142  CYPHOSOMA 

narrow  at  the  ambitus,  where  it  is  crowded  with  granules,  and  wide  at  the  upper  sur- 
face, where  it  is  depressed  and  nearly  nude  (PI.  XXVIII,  fig.  Id).  At  the  base  of  the 
area,  between  the  primary  tubercles  and  the  poriferous  zones,  there  is  a  short  row  of  small 
secondary  tubercles  (fig.  1  c),  which  extends  from  the  peristome  to  the  ambitus;  fig.  1  /i 
shows  the  base  of  this  segment  magnified  six  times;  the  small  secondaries  are  raised 
upon  bosses  (fig.  1  /i). 

The  tubercles  of  both  areas  are  nearly  of  the  same  size ;  the  boss  is  large,  with  feeble 
crenulations,  closely  embracing  the  mammillon,  Avhichis  very  prominent  (PI.  XXIX,fig.  1  d). 

The  base  is  concave,  and  the  mouth-opening,  one  third  the  diameter  of  the  test,  is  in 
a  slight  depression  (fig.  1  c).  The  peristome  is  divided  by  slight  incisions  into  ten  nearly 
equal-sized  lobes.  The  discal  opening  is  large  and  pentagonal.  The  mould  of  the  single 
ovarial  plate  descends  further  into  the  segment  than  either  the  antero-  or  postero- 
lateral ovarials  into  their  respective  areas. 

The  spines  of  this  Urchin  are  spatulate,  and  the  stem  is  extremely  smooth,  except  near 
the  milled  ring,  where  the  base  is  marked  by  fine  longitudinal  hues. 

Affinities  and  Differences. — The  spatulate  form  of  the  spines  distinguish  this 
species  from  C.  coroUare,  with  which  it  has  many  affinities  in  the  anatomy  of  the  test ; 
C.  spatuliferum  is,  however,  a  smaller  Urchin,  more  compressed  and  pentagonal,  less 
inflated  at  the  sides,  and  more  depressed  on  the  upper  side  than  C.  coroUare ;  the  surface 
of  the  test  is,  likewise,  rougher  in  consequence  of  the  numerous  small  tubercles  that 
project  sharply  from  the  plates. 

Locality  and  Stratigrajjhical  Position. — This  is  a  rare  species  in  the  Upper  Chalk  of 
Kent  and  Sussex.  The  type  specimens  of  the  Dixon  Collection  are  now  in  the  British 
Museum.  One  of  these  I  have  figured  in  PI.  XXVIII,  fig.  1 ;  and  a  still  larger  specimen, 
from  the  Rev.  T.  Wiltshire's  Cabinet,  in  PI.  XXIX,  fig.  1. 

CypHOSOMA  RADiATUM,  Sori(jnet,  1850.     PI.  XXIX,  figs.  2  a,  b,  c ;  figs.  3  a,  b. 

CrPHOsoMA  ?  (small  or  young),  Dixon.     Geol.  Sussex,  p.  x,  pi.  xxiv,  figs.  28 — 31,  1850. 

—  RADIATUM,  Sorignet.     bursins  foss.  du  Dep.  de  I'Eure,  p.  28,  1850. 

—  SIMPLEX,  i^orif*.     Morris's  Catalogue  of  Brit.  Foss.,  p.  74,  1854. 

- —  —         Woodward.     Mem.  Geol.  Surv.,  Decade  V,  App.,  p.  1,  1856. 

Phtmosoma  Heberti,   Besor.      Synopsis  des    Echinides  foss..   Supplement,  p.  450, 

1858. 
CyPHOSOMA  PERFECTUM,  Cotteau  tt  Triger  (pars).     Echinides   du  Depart,   de  la  Sarthe, 

p.  375,  1862. 
Phtmosoma  Heberti,  Dvjardin  et  Hupe.     Hist.  Nat.  des  Echinoderm.,  p.  508,  1862. 

—  SIMPLEX,  Dujardin  et  HupL  Ibid. 

Ctphosoma  r.\diatum,    Cotteau.      ^Paleontologie  Fran^nise ;    Ter.    Cret.,   pi.    11-1",   fio-s. 

10—14;  pi.  1148,  p.  609,  1864. 

Test  small,   subpentagonal,  convex  above,   base  concave;    ambulacra,   two  rows    of 


FROM  THE  UPPER  CHALK.  143 

tubercles,  eight  in  each,  with  large  confluent  areolae  at  the  ambitus ;  inter-ambulacra,  two 
rows  of  primary  tubercles,  nine  to  ten  in  each,  with  two  short  rows  of  small  secondaries 
at  the  base ;  primary  tubercles  prominent  at  the  ambitus,  small  and  inconspicuous  above ; 
areolse  large,  radiated,  and  nearly  confluent  at  the  middle,  very  small  above ;  poriferous 
zones  undulated,  unigeminal ;  pores  small. 

Dimensions. — Height  three  tenths  of  an  inch ;  transverse  diameter  six  tenths  of  an 
inch. 

Descrij)tion. — This  beautiful  little  species  occurs  in  the  hard  gritty  Chalk  of  Dover. 
The  test  is  more  highly  ornamented  than  any  of  the  preceding  forms ;  the  tubercles  at 
the  ambitus  are  highly  developed,  with  radiated  areolae,  and  nearly  all  of  the  same  size. 
On  the  upper  surface  they  are  proportionally  small.  The  ambulacral  segments  slightly 
project;  this  imparts  a  subpentagonal  form  to  the  body  (fig.  2  a).  There  are  two  rows 
of  tubercles  therein,  eight  in  each,  those  at  the  ambitus  being  very  large,  and  those  on 
the  upper  surface  very  smafl  (fig.  2  c).  The  areolae  of  the  large  ambital  tubercles  are 
confluent,  and  the  smaller  ones  are  separated  from  each  other  by  a  few  granules 
(fig.  2  c). 

The  poriferous  zones  are  narrow  and  much  undulated  (fig.  3  «)  ;  at  the  ambitus  the 
pores  are  small  and  unigeminal,  and  there  are  five  pairs  opposite  each  of  the  larger 
plates. 

The  inter-ambulacral  areas  are  a  little  wider  than  the  ambulacral,  with  two  rows  of 
tubercles,  nine  to  ten  in  each.  The  areolae  are  wide ;  those  at  the  ambitus  and  superior 
surface  have  a  radiated  border  at  the  circumference,  the  radii  being  formed  of  elongated 
granules  developed  into  a  pyriform  shape ;  (fig.  3  b)  represents  four  central  plates 
of  an  inter-ambulacral  segment  magnified  eight  times.  In  some  of  the  plates  small 
miliary  granules  are  introduced  within  the  rayed  circle. 

The  discal  opening  is  large,  and  of  an  elongated  pentangular  shape;  the  angle  cor- 
responding to  the  single  inter-ambulacrum  projecting  far  down  that  segment  (figs.  2  a 
and  b). 

Affinities  and  Differences. — This  species  in  its  general  facies  resembles  C.  spatdiferum, 
but  differs  from  it  in  having  the  tubercles  on  the  upper  surface  disproportionately  small 
when  compared  with  the  large  size  they  attain  at  the  ambitus  (figs.  2  b,  c).  This  character 
is  very  evident  when  fig.  2  c,  PI.  XXIX,  is  compared  with  fig.  1/  PI.  XXVIII.  The 
radiated  structure  of  the  areolae  is  likewise  another  good  diagnostic  character  between  these 
nearly  allied  forms.  M.  Cotteau  appears  to  consider  C.  Wetherelli  and  C.  spatdiferum 
as  varieties  of  C.  striatum ;  but,  after  a  careful  comparison  of  the  specimens  themselves 
and  with  each  other,  I  must  dissent  from  this  opinion.  However  much  the  tests  of 
JEchinida  per  se  may  resemble  one  another,  still  we  must  not  forget  that  the  shell  alone  is 
not  the  complete  body  of  the  animal,  and  that  without  its  spines  our  evidence  of  specific 
identity  is  incomplete :  for  example,  the  test  of  Hemicidaris  crenularis,  Ag.,  is  identical 
with  Hemicidaris  intermedia,  Flera. ;    but  the  spines  of  the  former  are  very  different 


144  SALENIDyE 

from  those  of  the  latter,  and  without  these  appendages  it  is  impossible  to  distin- 
guish the  test  of  the  one  Urchin  from  that  of  the  other,  and  the  same  conditions 
may  be  true  of  the  tests  of  other,  nearly  allied  forms.  C.  WethereUi  may  be  con- 
sidered a  variety  of  C.  coroUare  until  proof  to  the  contrary  is  discovered  ;  but  the 
structure  of  the  test  of  C.  spatuliferum  and  the  remarkable  form  of  its  flattened  spines, 
when  compared  with  the  test  and  spines  of  C.  coroUare,  afford  presumptive  evidence  that 
they  are  distinct  forms.  It  is  very  desirable  to  diminish  the  number  and  correct  the 
synonyms  of  species  in  our  lists ;  to  do  this,  however,  correctly  requires  much  literary 
research  and  a  critical  examination  and  comparison  of  the  specimens  themselves,  before 
a  true  solution  of  the  difficulty  can  be  arrived  at ;  and  in  doing  all  this  the  best  ob- 
servers very  often  confuse  analogy  with  identity  of  structure,  from  the  imperfect  materials 
upon  which  they  are  too  often  obliged  to  work. 

LocaJUy  and  Slratigrapldcal  Position. — Cyphosoma  striatum  is  usually  found  in  the 
hard,  gritty  beds  of  Lower  Chalk  near  Folkestone,  and  occasionally  in  the  Upper  Chalk 
with  flints  in  Sussex. 

The  type  specimen  figured  in  PI.  XXIX  belongs  to  the  Museum  of  the  Royal  School 
of  INIines.  I  have  examined  several  others  collected  by  my  kind  friend,  the  Rev.  T.Wiltshire, 
F.G.S.,  from  the  Lower  Chalk,  near  Folkestone,  where  he  found  it  associated  with 
Salenia  granulosa,  Forb. 

SALENID.E. 

Family  5. — Salenid^,  Wright,  1856. 

This  natural  family  nearly  corresj)onds  to  the  Salenies  of  MM.  Agassiz  and  Desor,  and 
is  distinguished  from  other  families  of  the  Echinodea  Endocydica  by  the  peculiar  structure 
and  great  development  of  the  apical  disc,  which,  besides  the  five  genital  and  five  ocular 
plates,  has  an  additional  or  sur-anal  plate,  developed  in  the  centre  of  the  disc,  immediately 
before  the  anal  opening ;  this  plate  in  some  genera  is  single,  in  others  it  is  composed  of 
from  one  to  eight  separate  elements. 

The  test  is  thin,  and  in  general  small,  spheroidal,  hemispherical,  or  depressed ;  the 
ambulacral  areas  are  always  narrow,  straight,  or  flexuous,  with  two  rows  of  granules  or 
small  tubercles,  that  alternate  with  each  other  on  the  margins  of  the  area. 

The  poriferous  zones  are  narrow  ;  the  pores  unigeminal,  except  near  the  peristome,  where 
they  fall  into  oblique  ranks  of  threes. 

The  inter-ambulacral  areas  are  wide,  with  two  rows  of  primary  tubercles,  which  have 
large  bosses  and  crenulated  summits ;  in  Acrosalenia  and  Pseudosalenia  the  tubercles  are 
perforate,  in  Peltastes,  Goniojjhorus,  and  Salenia  they  are  imperforate.  The  mouth-opening 
differs  in  size  in  the  different  genera ;    the  peristome  is  more  or  less  decagonal,  and 


SALENID^.  145 

sometimes  deeply  notched,  or  only  feebly  indented.  The  jaws  are  known  in  one  genus, 
in  which  they  resemble  those  of  Hemicidaris. 

The  spines  in  Acrosalenia  are  long,  slender,  angular,  or  flattened,  and  the  surface  of 
the  stem,  although  apparently  smooth,  is  covered  with  very  fine  longitudinal  lines.  In 
Pseudosalenia  they  are  enlarged,  ovoid,  snb-glandiform,  and  more  or  less  granular;  in 
PeUastes  and  Salenia  they  are  elongate,  aciculate,  straight,  curved,  or  bent. 

From  a  misconception  of  the  true  relative  position  of  the  elements  of  the  apical  disc  in 
this  family,  much  confusion  exists  in  the  works  of  diffei-eut  authors  in  the  description  of 
this  part  of  the  test.  "  The  great  difficulty  in  the  study  of  this  group,"  says  M.  Desor,' 
"  is  to  find  the  place  of  the  madreporiform  body  ;  we  are  consequently  embarrassed  when 
we  attempt  to  assign  the  lateral  parts  to  the  longitudinal  axis  of  these  animals,  unless  we 
admit  that  the  sur-anal  replaces  the  madreporiform  body ;  but  this  would  be  contrary  to 
all  analogy,  because  in  all  the  other  Cidarides  the  madreporiform  body  is  an  integral  part  of 
one  of  the  genital  plates.  M.  Agassiz  got  rid  of  the  difficulty  by  means  of  an  hypothesis, 
by  admitting  that  the  sur-anal  plate  is  invariably  placed  in  the  plane  of  the  animal,  that  it 
therefore  could  only  be  anterior  or  posterior;  hence  his  two  divisions  in  the  genus  Salenia,  the 
first  with  a  sur-anal  plate  posterior,  and,  consequently,  with  the  periprocte  excentral  and 
before;  the  second  with  the  sur-anal  plate  anterior,  and,  consequently,  with  the  periprocte 
excentral  and  behind."^ 

Professor  Johannes  Midler  assigns  the  left  posterior  genital  plate  as  the  bearer  of  the 
tiiadreporiform  body  in  Saletiia  persona/a.  "  Dies  wird  auch  durch  die  Salenien  bestatigt, 
wo  die  Langsachse  durch  die  plaque  suranale  vor  dem  After  bestimmt  wird.  An  einem 
im  mineralogischen  Museum  aufbewahrten  ausgezeichnet  schonen  Exemplar  der  Salenia 
personafa.  Ag.,  mit  vorderem  After,  Taf.  I,  fig.  9,  ist  die  linke  hintere  Genitalplatte  poros 
und  Madreporenplatte."  ^ 

I  have  selected  fine  specimens  of  PeUastes  Wriglitii,  Desor,  from  the  Lower  Green- 
sand,  PeUastes  Austeni,  Forbes,  from  the  Lower  Chalk,  and  Salenia  petalifera,  Desniarest, 
from  the  Upper  Greensand,  and  in  all  of  these  the  madreporiform  body  occupies  the 
surface  of  the  right  anterior  genital  plate,  as  in  the  Cidaridce,  Hemicidarida,  Biademadce, 
and  EcJiinida.  The  sur-anal  plate  is  central,  and  the  anal  opening  posterior  in  a  line  with 
the  axis  of  the  body,  or  inclined  to  the  right  side.  In  fact,  the  madreporiform  body  and 
sand  canal,  whatever  their  true  functions  may  be,  have  the  same  position  in  all  the 
Echinidea,  recent  and  fossil,  which  I  have  examined,  and  probably  the  same  in  all 
Echinodermata.  Professor  Midler's  mistake,  therefore,  may  have  arisen  from  jjlacing  the 
Salenia  in  a  false  position  before  him.  The  study  of  the  apical  disc  in  the  Acrosalenia 
reveals  the  true  relation  of  its  elements  to  each  other,  and  jjroves  that  the  sur-anal  plate 

1  '  Synopsis  des  i5chiiiiiJes  fossiles,'  p.  138. 

2  For  further  details  on  this  subject,  M.  Agassiz's  'Monographies  d'Echinodermes:  premiere  Monographie 
des  Salenies,'  may  be  consulted. 

3  Job.  Miiller,  '  Ueber  den  Ban  der  Echinodernien,'  p.  7. 

19 


146 


SALENID^. 


has  nothing  in  common  with  the  spongy  madreporiform  body  which  occupies  tlie  surface 
of  the  right  anterior  genital  plate  (PL  XV,  fig.  4,  a,  t).  I  had  the  good  fortune  to  make 
this  discovery  some  years  ^  ago,  when  figuring  and  describing  Acrosalenia  hemicidaroides, 
which  urchin  has  furnished  a  key  to  the  true  relation  of  the  bilateral  parts  to  the  longi- 
tudinal axis  of  the  SALENiDiE.     On  this  point  M.  Desor  observes  : 

"  Nous  devons  en  outre  a  M.  Wright  une  autre  decouverte  plus  iraportante,  celle  du 
corps  madreporiforme,  qui  fait  partie  integrante  de  I'une  des  plaques  genitales  corame  dans 
les  autres  Cidarides.  Or  comme  nous  savons  maintenant  que  cette  plaque  a  une  position 
fixe  dans  tons  les  oursins,  nous  sommes  par  la  meme  en  raesure  de  determiner  Pavant  et 
I'arriere  de  ces  animaux ;  et  puisque  les  plaques  sur-anales  sont  situees  eu  arriere  de  cette 
plaque,  il  s'ensuit  que  le  periprocte  se  trouve  reellement  refoule  en  arriere.  II  ne  peut 
des-lors  plus  etre  question  d'Acrosalenies  a  periprocte  eccentrique  en  avant,  corame  on 
supposait  que  c'etait  le  cas  de  \' Acrosalenia  tuberculosa"  &c. 

"  II  n'arrive  que  trop  souvent  que  le  disque  apicial  manque,  et  dans  ce  cas,  il  est  tres 
difficile  de  distinguer  les  Acrosalenies  du  genre  Hemipedina  decrit-ci-dessus.  Cependant, 
comme  par  suite  du  refoulement  du  periprocte  en  arriere  la  plaque  genitale  impaire  ou 
posterieure  gagne  plus  que  les  autres  sur  le  test,  on  peut  encore,  d'apres  M  Wright, 
reconnaitre  la  place  de  cette  plaque  meme  dans  les  individus  depourvus  d'appareil  apicial." ' 


Family.     Sections. 


Genera. 


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A  Table  showing  the  Classification  of  the  Salenid^. 

Diagnosis. 
Ambulacral  areas   straight,   large,  with    two   rows   of  small , 
tubercles  ;    apical  disc  small  and  not  prominent ;    sur-anal  plate  I  Acrosalenia  Ao-assiz 
composed  of  one  or  many  pieces  granulated   on  the   surface ; 
vent  posterior  and  central  in  the  axis  of  the  test ;  spines  long. 

Ambulacral  areas  narrow,  flexed,  with  two  rows  of  granules  ; 
apical  disc  prominent,  not  granulated,  and  marked  with  impres- 
sions ;  vent  exceutral  posterior,  in  the  axis  of  the  test ;  spines  I 
'•enlarged,  ovoid,  sub-glandiform,  more  or  less  granular.  J 

Inter-ambulacral  tubercles  moderate;  apical  disc  large  and] 
prominent;  genital  plates  in  the  form  of  elongated  lobes ;  sur- I 
anal  plate  single ;  vent  posterior  and  central  in  the  axis  of  the  | 
test. 


Pseudosalenia,  Cott. 


I  Peltustes,  Agassiz. 


—      s- 


luter-ambulacral  tubercles  large,  few  in  number ;  apical  disc 
large,  and  forming  a  regular   pentagon,  with  elevated  angular  1 
carinae  independent  of  the  sutures  ;  sur-anal  plate  angular;  vent    <?<'«»o?^'""«*.  Agassiz. 
large,  escentral,  oblong,  and  posterior.  j 


Inter-ambulacral  tubercles  large ;  apical  disc  wide  and  very  solid, 

with  an  undulated  circumference  ;  surface  of  the  large  plates 

ornamented  with  punctuations  or  sculptured  figures  along  the 

line  of  the  sutures  ;    sur-anal  plate  single ;    vent  posterior  ex- 

>  central  and  directed  towards  the  right  side. 


V  Salenia,  Gray. 


^  Wright,  'Annals  and  Magazine  of  Natural  History,'  2nd  series,  vol.  viii,  p.  261. 
2  '  Synopsis  des  Echinides  fossiles,'  p.  140. 


SALENID^.  147 

M.  Cotteau  thus  describes  the  family  "  Salenidees,"  Wright : — Pores  disposed  in  single 
pairs;  ambulacra  sometimes  large,  straight,  and  presenting  a  double  range  of  small 
tubercles  ;  sometimes  narrow,  and  undulated,  and  garnished  with  granules ;  interambu- 
lacral  tubercles  few  in  number,  largely  developed,  perforated,  or  imperforate,  always 
crenulated.  Peristome  sub-decagonal  and  furnished  with  entailles.  Periprocte  excentric 
and  posterior,  placed  in  the  axis  of  the  animal  or  inclined  a  little  to  tlie  right  side. 
Apical  disc  very  large,  solid,  most  often  marked  with  deep  depressions,  composed  of  five 
ovarial  plates  and  five  ocular  plates  perforated,  with  one  or  many  sur-anal  plates  which 
determine  the  excentricity  of  the  periprocte.  Madreporiform  plate  distinct,  diSerent 
from  the  others  by  its  spongy  aspect  and  sometimes  by  a  simple  laceration,  a  fissure  more 
or  less  large  which  corresponds  to  the  genital  pore  and  seems  directed  invariably  to 
the  left  side.  The  spines  are  sometimes  elongate,  aciculate,  or  sub-cylindrical,  fm-nished 
with  fine  longitudinal  stria3  in  the  Acrosalenia  heiuicidaroides,  Wright,  sometimes 
enlarged,  ovoid,  sub-glandiform,  more  or  less  granular,  as  in  the  Pseudosalenia  tuberculosa. 

The  SaleniDjE  are  divided  into  two  natural  groups. 

1st.  The  Acrosalenia  have  narrow  ambulacra  gradually  enlarged  towards  the  oral 
aperture  and  provided  with  perforated  tubercles  more  or  less  developed ;  the 
peristome  is  divided  into  two  lobes  by  deep  incisions ;  the  apical  disc  is  very  large  and 
provided  with  a  sur-anal  plate  composed  of  one  or  many  elements ;  in  consequence  of 
the  number  of  small  sur-anal  plates,  and  their  feeble  union  with  each  other,  they  are 
seldom  preserved. 

2nd.  The  SalenicB,  and  the  genera  dismembered  from  them,  have  narrow  ambulacra, 
often  undulated  and  garnished  with  tubercles;  their  peristome  is  feebly  incised;  the 
apical  disc  is  large  and  solid,  projecting  beyond  the  surface,  and  more  or  less  deeply 
marked  with  impressions  at  tlie  sutures  of  the  plates. 

The  Acrosalenia:  resemble  Hemicidaris  and  llypodiadema,  except  in  the  sti'ucture 
of  the  apical  disc,  and  when  this  portion  is  absent  it  is  often  difficult  to  determine  the 
genus  to  which  the  mutilated  specimen  belongs ;  but  the  great  size  of  the  discal  aperture, 
and  the  extension  of  the  single  ovarial  plate  into  the  single  inter-ambulacrum  readily 
enable  the  trained  eye  of  the  observer  to  distinguish  it  from  Hemicidaris. 

The  SalenicB,  on  the  other  hand,  resemble  the  CidariDvE  by  their  narrow  sub-flexuous 
ambulacra,  furnished  with  granules,  their  wide  inter-ambulacral  areas,  their  large  primary 
tubercles,  and  the  inflated  ovoid  or  sub-glandular  spines,  sometimes  supported  on  them  ; 
their  peristome  is  likewise  feebly  incised,  like  that  of  Cidaris. 

The  Acrosalenice  form  only  a  single  genus,  the  species  of  which,  with  one  exception, 
are  distributed  throughout  the  Jurassic  rocks. 

The  Siilenm  have  certain  distinctive  characters  l)y  which  they  are  readily  distinguished 
from  the  Acrosalenice.  1st.  Their  tubercles  are  all  imperforate,  and  2nd,  the  position  of  the 
vent,  or  periprocte,  is  always  excentric  and  posterior;  sometimes  it  is  situated  in  the  axis 
of  the  body,  and  sometimes  out  of  the  axis,  and  inclines  to  the  right  side.    For  this  reason 


J48  SALENIDiE. 

MM.  Af^assiz  and  Desor  have  separated  from  the  true  Saleni(B  the  genera  Peltastes  and 
Hyposaleuia.  By  the  same  authors  a  doubt  has  been  suggested  about  the  vahie  of  this 
character,  as  it  may  be  only  an  accidental  and  variable  condition  ;  to  this  objection 
M.  Cotteau  replies,  "  that  he  has  examined  more  than  four  hundred  specimens  of  Salenice 
appertaining  to  the  different  stages  of  the  Cretaceous  formations,  and  representing  almost 
all  the  known  species,  many  among  which,  such  as  Peltastes  acanthoides,  P.  Studeri,  Salenia 
2}etalifera,  8.  Predensis,  and  8.  Bourgeoisi  present  characters  that  are  clearly  defined. 
Nevertheless  we  have  recognised  in  each  of  those  species  that  the  periprocte,  whether 
in  the  axis  of  the  animal  or  out  of  the  axis,  occupies  a  place  which  is  invariably  the  same." 

The  structme  of  the  apical  disc,  and  the  lines  and  impressions  marked  thereon,  afford 
a  character  of  secondary  importance,  for  although  the  general  outline  of  these  sutures  is 
remarkably  constant,  still  there  are  exceptions  which  show  that  caution  must  be  exercised 
in  using  it,  along  with  others,  in  the  determination  of  species.  The  size  of  the  ambulacra, 
and  the  number  and  magnitude  of  the  granules  contained  therein ;  the  form  of  the 
test,  the  size  of  the  inter-ambulacral  tubercles ;  the  dimensions  of  the  oral  aperture,  the 
structure  of  the  peristome,  and  the  depth  of  the  incisions  or  eutailles,  collectively  form 
good  specific  characters  on  which  we  can  rely. 

M.  Cotteau  divides  the  family  Salenid^  into  six  genera,  of  which  he  gives  the 
opposable  characters  in  the  following  table.^ 

A.  Ambulacra  large,  straight,  furnished  with  small  tubercles;  apical  disc 

with  a  compound  sur-anal  plate,  the  elements  of  which  are  covered  K.  Acrosalenia 
with  granules. 

B.  Ambulacra  narrow,  sub-undulated,  furnished  with  granules;    apical 

disc  large,  prominent ;  sur-anal  plate  single  ;  elements  large  shield- 
shaped,  marked  by  regular  impressions. 

o.  Tubercles  perforated. 

X.  Periprocte  excentral  and  posterior,  situated  in  the 


[  PSEUDOS 

XX.  Periprocte  excentral  and  posterior,  situated  with-  ) 


.  ,    . OSALENIA. 

axis  of  the  animal 


,  f  Heterosa],enia. 

out  the  axis  of  the  body  ) 

h.  Tubercles  imperforate. 

X.  Periprocte  excentral  and  posterior,  situated  in  the"") 

axis  of  the  animal.  „ 

,     .    II         1     •  ,.        ■,.  ^Peltastes. 

1.  Ambulacra  destitute  of  poriferous  impres- 

sions J 

2.  Ambulacra  furnished  with  poriferous  im- )  _, 

\  GONIOPHORUS. 

pressions  ; 

XX.  Periprocte  excentral  and  posterior,  situated  with-^ 

out  the  axis  of  the  body  and  inclined  to  the  (  Salenia. 
right  side  \ 

1  '  Paleontologie  Franjaise  ;  Terrain  Cretace,'  tom.  vii,  p.  90. 


PELTASTES.  149 

The  family  Salenid^  commenced  their  life-career  in  the  lower  zone  of  the  Inferior 
Oolite.  Acrosalenia  abound  in  the  Inferior  Oolite  and  the  Cornbrash ;  and  one  is  found  in 
the  Coralline  Olite.  Pseudosalenia  was  discovered  in  the  Corallian  of  the  Haut  Jura. 
Ileterosalenia  is  represented  by  one  solitary  species  in  the  Chalk  with  Hippurites  (Senonieii 
Inferieur).  Peltmtes  and  Gonioj^horns  are  found  chiefly  in  the  Lower  Cretaceous.  Salenice 
occur  in  the  Lower,  Middle,  and  Upper  Cretaceous  rocks  ;  and  in  the  Tertiary  Numraulitic 
limestone  of  Biarritz,  are  represented  by  a  curious  species,  Salenia  Pellati,  recently  found 
in  that  formation.  Our  present  seas  contain,  we  are  told,  a  representative  form  of  this 
family,  which  was  recently  dredged  up  off  the  American  coast  by  the  deep-sea  dredging- 
operations  performed  in  1869  ;  beyond  the  alleged  fact  I  know  nothing  whatever  of  the 
genus  to  which  this  existing  form  belongs. 


Genus — Peltastes,  Acjassiz,  1838. 
Salenia  (pars),  Agassiz,  1S3S.  Hyposalenia,  Desor,  1856. 

Test  small,  circular,  more  or  less  inflated  above,  and  almost  flat  below ;  pores  simple 
in  the  zone  and  crowded  near  the  peristome ;  ambulacra  straight,  or  slightly  flexuous,  fur- 
nished with  two  rows  of  small,  close-set,  homogeneous  mammillonated  granules.  Inter- 
ambnlacra  large,  provided  with  two  rows  of  large,  crenulated,  imperforate  tubercles. 

Mouth-opening  moderate  in  size,  peristome  divided  into  unequal  lobes  by  feeble 
incisions.  Periprocte  excentral  and  posterior,  situated  in  the  line  of  the  animal's  axis. 
Apical  disc  shield-shaped,  composed  of  large  plates,  more  or  less  undulated  at  the 
border;  the  disc  covers  in  general  a  large  portion  of  the  upper  surface  of  the  test,  and 
is  marked  by  sutural  impressions  and  striae  that  vary  in  the  different  species ;  the  right 
antero-lateral  ovarial  plate  has  an  oblong  fissure  always  directed  from  right  to  left, 
corresponding  to  the  oviductal  pore  and  representing  the  madreporiform  body. 

Peltastes  in  its  general  form  and  structure  resembles  Salenia ;  it  is  distinguished  from 
the  latter,  however,  by  the  position  and  direction  of  the  periprocte,  which  is  excentral, 
and  directed  obliquely  backwards  and  outwards  and  towards  the  right  side ;  the  ambulacra 
likewise  are  less  flexed,  the  mouth-opening  is  smaller  and  lies  in  a  deeper  depression ; 
the  madreporiform  fissure  in  the  right  antero-lateral  ovarial  plate  is  smaller. 

The  genus  Peltastes  was  established  in  1838  by  Professor  Agassiz  j  and  in  184G 
MM.  Agassiz  and  Desor  comprised  in  the  genus  all  the  Saleniad^  in  which  the  periprocte 
was  situated  in  a  line  with  the  axis  of  the  animal,  and  this  forms  the  leading  character 
by  which  it  is  distinguished  from  Salenia. 

The  genus  Peltastes  is  special  to  the  Cretaceous  formations;  it  commences  with  some 
remarkable  forms  in  the  Lower  Greensand,  appears  in  full  force  in  the  Upper  Greensand  and 
Lower  Chalk;  becomes  rare  in  the  Upper  Chalk,  and  finally  disappears  from  its  upper  stages. 


150  PELTASTES. 


A.  Sjjecles  fro7)i  the  Loiver  Greensand  or  Neocomian. 

Peltastes  Wrightii,  Desor.     PI.  XXX,  fig.  1  a—f,  fig.  2. 

Salenia  punctata,  Forbes.     In  Morris'  Catalogue  of  British  Fossils,  2nd  ed., 

p.  89,  1854. 
—  —  Woodward,  Memoirs  of  Geol.  Surv.,  App.  to  Decade  V, 

p.  7,  1856, 
Hyposalenia  Wiughtii,       Besor.     Synopsis  des  Echinides  fossiles,  p.  148,  1856. 
Peltastes  —  Cotteau.     Paleuntologie  Fran9aise  ;  Terrain  Cretace,  tome 

vii,  pi.  1028,  figs.  1—7. 

Biarjnosis. — Test  circular,  upper  surface  convex,  sides  inflated,  under  surface  flat, 
ambulacra  narrow,  slightly  flexuous,  with  two  rows  of  granules  fifteen  in  each,  equal  in 
size,  and  manimillated  ;  poriferous  zones  slightly  flexed,  pores  unigeminal,  set  in  oblique 
pairs,  and  multiplied  around  the  peristome ;  inter-ambulacra  wide,  with  five  or  six  large 
prominent  tubercles,  increasing  in  size  from  the  peristome  upwards.  Apical  disc  very 
large,  convex,  subcircular,  plates  smooth,  sutures  marked  with  isolated  points,  periprocte 
transversely  oblong,  a  little  prominent;  mouth-opening  large,  peristome  divided  by 
feeble  indentations  into  ten  lobes. 

Dimensions. — Height  six  tenths  of  an  inch  ;  transverse  diameter  one  inch. 

Bescription. — Tiiis  beautiful  typical  form  of  Peltastes,  and  the  oldest  we  at  present 
know,  appears  in  our  lists  of  English  fossils  as  Saletiia  punctata,  one  of  the  synonyms  of 
Peltastes  stellulatus.  A  comparative  study  of  specimens,  however,  convinced  M.  Desor 
that  the  identification  was  erroneous  ;  and  he  described^  our  Earringdon  urchin  as  a  well- 
marked  and  distinct  species,  resembling  Peltastes  stellulatus,  but  separated  from  it  in 
havinc  a  more  inflated  test,  with  more  numerous  and  less  prominent  tubercles,  the  apical 
disc  thinner  and  smoother,  and  marked  only  with  some  isolated  punctations. 

The  test  is  circular,  the  sides  are  a  little  inflated,  and  the  upper  surface  is  convex  and 
depressed ;  the  ambulacral  areas  are  narrow  and  very  slightly  flexed  with  two  rows  of 
mammillated  granules,  about  fifteen  in  each.  They  are  very  uniform  in  size  and  arrange- 
ment throughout  the  area,  except  at  the  base,  where  two  pairs  are  a  little  larger ;  a  line 
of  microscopic  granules  down  the  middle  of  the  area  divides  the  larger  lateral  rows  from 
each  other  (PI.  XXX,  fig.  1  e).  The  poriferous  zones  are  wide  for  so  small  a  test,  and 
the  pairs  of  pores  are  obliquely  but  very  regularly  arranged  in  a  unigeminal  series ;  near 
the  peristome,  however,  they  become  a  little  more  crowded  and  doubled. 

The  inter-ambulacral  areas  are  wide,  and  in  the  large  specimen  I  have  figured  fig.  1  a 


1  <■ 


Synopsis  des  Echinides  fossiles,'  p.  148. 


FROM  THE  LOWER  GREENS  AND.  151 

there  are  six  plates  in  eacli  column ;  the  tubercles  increase  in  size  from  the  peristome 
upwards,  so  that  the  three  upper  pairs  of  tubercles  are  the  largest  and  most  prominent 
of  the  series  (fig.  1  d  and  fig.  1/).  A  few  large  mammillated  granules,  unequal  in  size, 
are  arranged  round  the  areola  and  in  the  miliary  zone  ;  a  double  row  of  smaller  granules 
occupy  the  middle  space ;  the  tubercles  are  raised  upon  large  bosses  with  deeply  crenu- 
lated  summits,  and  the  mammillon  is  prominent,  projecting,  and  imperforate  (fig.  1/). 

The  apical  disc  is  very  large,  convex,  subcircular,  and  entirely  smooth,  presenting  in 
the  line  of  its  sutures  two  or  three  isolated  superficial  punctations  in  some  of  them 
(fig.  1  b) ;  the  sur-anal  plate  occupies  the  centre  of  the  disc,  and  is  situated  immediately 
before  the  vent ;  in  one  example  (fig.  2)  however,  it  is  abnormal  and  rudimentary,  and 
forms  an  exceptional  variety  in  an  otherwise  remarkably  regular  and  symmetrical  structure. 
Of  the  many  specimens  of  this  Urchin  that  have  passed  through  my  hands  this  is  the  only 
exception  that  has  come  under  my  notice.  All  the  ovarial  plates  are  perforated  near  the 
centres  of  each ;  the  madreporic  laceration  is  small,  but  very  distinct  in  the  rio-ht 
antero-lateral  ovarial  (fig.  1  h).  The  periprocte  is  sub-elliptical,  rounded  anteriorly,  an o-ular 
posteriorly,  and  somewhat  elevated  and  inflated  at  the  border  (fig.  1  b  and  fig.  2). 

The  base  is  flat  and  the  mouth-opening  large,  one  half  the  diameter  of  the  test  (fio-.  1  c). 
The  peristome  is  circular  and  divided  by  feeble  incisions  into  ten  nearly  equal-sized 
lobes. 

Affinities  and  Differences. — This  species  presents  great  uniformity  in  its  specific 
characters,  after  a  careful  examination  of  a  great  many  specimens  I  have  found  very  little 
variation  from  the  type  form  I  have  figured  and  described.  This  specimen,  belono-ino-  to 
the  British  Museum,  is  unexceptionally  large,  and  perfect  in  all  its  parts.  Smaller 
specimens  are,  however,  equally  good  for  description.  Tlue  Sponge-gravel  in  which  this 
Urchin  is  most  commonly  found  is  in  general  a  very  bad  matrix  for  the  preservation  of  the 
tests  of  Echinidse ;  when  shielded  by  a  ferruginous  crust,  derived  from  the  matrix,  the 
more  delicate  portions  of  the  urchin  are  wonderfully  preserved.  P.  Wrightii  resembles 
P.  stellulaius ;  it  is  separated  from  that  form  by  having  a  greater  number  of  less  promi- 
nent tubercles  in  the  area ;  the  apical  disc  is  likewise  thinner  and  smoother,  and  the  sutural 
punctations  are  more  isolated  and  more  feebly  marked. 

Locality  and  Stratigraphical  Position. — I  have  collected  Peltastes  Wrightii  from   the 
Sponge-gravel  bed  of  the  Lower  Greensand  near  Farringdon,  Berks;  it  has  been  found 
likewise  in   the  Lower  Greensand  at  Hythe,  Kent;   and  at  Atherfield  and  Sandown 
Isle  of  Wight ;  it  is,  therefore,  a  true  Neocomian  or  Lower  Greensand  form. 

History. — This  species  is  a  very  distinct  form,  and  has  been  separated  by  Professor 
Desor  from  P.pimctatus,  with  which  it  had  been  identified  by  most  of  our  English  authors. 
The  accuracy  of  this  determination  has  been  sanctioned  by  M.  Cotteau,  who  has  given  a 
very  good  description  of  the  species,  with  excellent  figures  thereof,  in  his  great  work  on 
the  Cretaceous  Echinida3,  in  the  '  Paleontologie  Frangaise.' 


152 


PELTASTES. 


Peltastes  stellulatus,  Agassiz,  1846.     PL  XXXI,  figs.  1,  2,  3  ;  PI.  XLI,  fig.  1  a^g. 


SaLENIA  STELLL'LATA, 


Agassi:.      Monog.   des  Saleiiies,   pi.   ii,  figs.  2.5 — 32,   p. 

15,  1838. 
Agassiz.     Ibid.,  pi.  iii,  figs.  1 — 8,  p.  16. 
Agassiz.     Echin.  foss.  de  la  Suisse,  pi.  xxiii,  figs.  6 — 10, 

p.  90,  1840. 
Agassiz.     Ibid.,  figs.  11  — 15,  18-10. 
Agassiz  et  Desor.     Cat.  raison.  des  Enhinides,  Ann.  Sc. 

Nat,  3e  ser.,  torn,  vi,  p.  342,  1846. 
Agassiz  et  Desor.     Ibid. 
—  Marcou.     Jura  salinois,  Me'm.  Soc.  Geol.  de  France,  2eser., 

t.  iii,  p.  140,  1848. 
pentagonifeba,  A.  Gi-as.  Ours.  foss.  de  I'lsere,  p.  29,pl.  i,  figs.  11,12,1848. 
Bronn.     Index  Palseontologicus,  p.  1008,  1849. 
D'Orbigng.     Prod,  de  Paleont.  strat.,  t.  ii,  p.  89,  1850. 
VOrbigmj.     Ibid. 

Cotteau.     Catal.  des  Echinid.  ne'ocomiens,  1851. 
Bronn.     Leth.  Geognost.,  Kreidegeb.,pl.  xsix,  fig.  5,  1852. 
Desor.     Synops.  des  Echinid.  foss.,  pi.  xx,  figs.  6 — 8,  1856. 
Desor.     Ibid. 

Pictet.     Trait(?  de  Paleont.,  2e  ed.,  t.  iv,  p.  248,  1857. 
Pictet.     Ibid. 
Ibid. 
Ibid. 


-  areolata, 

stellulata, 

areolata, 

Peltastes  stellulatus 

—        punctata, 


SaLENIA  STELLUL.4.TA, 

Peltastes       — 
—      punctata, 

Peltastes  stellulata, 


Hyposalenia     — 

—  punctata, 

Peltastes  stellulata, 

—  punctata, 

—  PENTAGONIFERA,  PiCiTei. 

—  COURTAUDINA,      Pictet. 


—  stellulata, 

Hypos.alenia    — 
Peltastes  stellulatus, 


Leymerie  et  Raulin.     Geol.  de  I'Yonne,  Stat.  geol.  du  dep. 

de  I'Yonne,  p.  420,  1858. 
Leymerie  et  Raulin.     Ibid. 

Cutteau.     Ech.  foss.  de  I'Yonne,  pi.  54,  figs.  1—10,  1859. 
Cotteau.     Paleontol.  Fran9aise ;  Terrain  Cretace,  pi.  1023, 

p.  100,  1862. 


Diapwsis. — Test  small,  circular,  convex  above,  flat  below,  poriferous  zones  straight, 
formed  of  oblique  pairs,  ambulacra  straight,  two  rows  of  homogeneous  mammillated 
granules,  set  closely  together,  fourteen  in  each  row.  Inter-ambulacra  wide,  two  rows  of 
tubercles,  five  in  a  row,  unequal  in  size,  large  at  the  ambitus,  and  small  near  the  base ; 
apical  disc  very  large,  round,  and  depressed ;  sutures  well  marked  with  isolated  points,  and 
fine  incisions ;  madreporic  fissure  small,  distinct,  and  surrounded  by  an  elevation  of 
the  plate. 

Dimensions. — Height  three  tenths  of  an  inch  ;  transverse  diameter  half  an  inch. 

Description. — The  table  of  synonyms  affords  evidence  how  changes  of  form  in  certain 
parts  of  an  Urchin  lead  to  confusion  in  the  identification  of  the  species,  and  how  impossible 
it  is  to  define  in  a  few  words  certain  organisms  among  which  the  same  structures  vary  much 


FROM  THE  LOWER  GREENS  AND.  153 

in  different  individuals  with  age  and  the  changing  conditions  of  their  existence.  The 
apical  disc  of  Peltastes  stellulatus,  Ag.,  is  one  of  these  ;  M.  Cotteau  remarks' 
that  the  ovarial  plates  are  sometimes  almost  smooth,  and  present  Jiardly  any  isolated 
points,  as  in  P.  pentagoniferus,  Gras.  In  certain  examples  the  number  of  these  points 
augment  sensibly,  and  the  plates  remaining  perfectly  smooth,  the  lines  of  the  sutures  are 
punctuated  {P.  pundatus,  Ag.).  Instead  of  isolated  points,  the  sutures  are  often  marked 
with  lines  or  incisions  which  extend  along  the  surface  of  the  plates,  and  give  to  the  apical 
disc  a  very  remarkable  parsley-leaved  aspect  (P.  stellulatus.  Kg.).  Sometimes  this  charac- 
ter is  exaggerated ;  the  incisions  become  deep,  and  penetrate  even  into  the  interior 
of  the  plates,  which  unite  at  certain  points,  and  produce  a  remarkable  variety  of  disc  seen 
in  certain  specimens  collected  from  the  calcaires  a  Ecldnospatagus  cordiformis  in  the 
environs  of  Auxerre.  In  other  examples,  the  plates  independent  of  the  points,  more  or 
less  elongated  which  exist  on  the  suture,  ai'e  bordered  by  little  flexuous  bourrelets,  which 
become  attenuated  as  they  approach  the  centre,  as  in  P.  Court audiims,  Cot.  These  varie- 
ties, when  studied  separately,  as  they  were  discovered  by  different  observers,  were 
regarded  as  so  many  distinct  types  ;  but  a  careful  comparison  of  the  series  has  taught  M. 
Cotteau  that  they  are  only  so  many  varieties  of  the  same  species.  The  admirable  figures 
given  of  these  variations  fully  confirm  my  learned  friend's  conclusions  on  the  unity  of  the 
species.  The  structure  of  the  apical  disc  forms,  therefore,  an  important  character  in  the 
history  of  this  species ;  and  as  the  observations  that  have  been  made  upon  the  differences 
noted  on  the  ornamentation  and  sculpture  of  its  elements  are  applicable  to  other  forms  of 
Peltastes,  the  careful  study  of  this  structure  requires  thoughtful  notice  in  making  a 
diagnosis  of  all  supposed  new  forms  of  Salenidse. 

The  ambulacral  areas  are  quite  straight  (fig.  1  b),  and  between  the  two  lateral  rows 
of  mammillated  granules  a  zigzag  line  of  microscopic  graniUets  extends  from  the  base  to 
the  summit  (fig.  3  b). 

The  inter-ambulacral  areas  are  wide  and  furnished  with  two  rows  of  tubercles  having 
crenulated  bosses  and  imperforate  mammillous;  they  are  prominent,  unequal  in  size, 
largest  at  the  ambitus,  and  decrease  towards  the  peristome;  very  large  mammillated 
granules  fill  up  the  miliary  zone  and  form  very  regular  circlets  around  the  primary 
tubercles.  Between  these  granules  in  well-preserved  specimens  a  number  of  microscopic 
granulets  are  seen  closely  arranged  around  their  base. 

The  mouth-opening  lies  in  a  slight  depression,  and  the  peristome  is  divided  into  ten 
lobes  by  feeble  incisions,  with  reflected  borders  (fig.  2). 

The  vent  is  transversely  oval  (fig.  3  a),  and  the  periprocte  has  a  slightly  elevated  and 
inflated  border. 

A  variety  of  "Peltastes  stellulatus,  Ag.,  figured  in  detail  (PI.  XLT,  fig.  I  a — g),  was  col- 
lected by  the  Rev.  T.  Wiltshire,  F.G.S.,  from  a  greenish  yellow  band  of  the  Red  Chalk 
at  Speeton,  Yorkshire.     The  trite  position  of  this  specimen  was  between  the  upper  por- 
1  '  Pal^ontologie  Fran^aise,  terrain  Cr^tace,'  t.  vii,  p.  102. 

20 


154  PELTASTES 

tion  of  the  Gault  and  the  base  of  the  Upper  Greeiisand ;  this  stratum,  about  nine  feet 
thick,  contained  small  GryphtecB  and  TcrebratuJa  semit^lobosm  with  the  Peltasfes ;  and 
few  fossils  besides  these.  The  apical  disc  (fig.  1  b)  shows  many  punctuations  in  the  line 
of  the  sutures ;  one  entire  ambulacraj  magnified  four  times,  is  shown  (fig.  1  /),  and 
one  entire  inter-ambulacra,  equally  enlarged,  in  fig.  \  e ;  the  structure  of  a  single  plate, 
magnified  six  times,  in  fig.  2  y,  and  the  disc  isolated,  magnified  foiu*  diameters,  is  shown 
in  fig.  1  d.  All  these  figures  are  drawn  with  the  utmost  care  and  truthfulness  for 
comparison  with  other  varieties  of  this  species  collected  from  the  Sponge-Gravel  of 
Farringdon  and  figured  in  PI.  XXXI,  figs.  1 — 3.  For  an  account  of  the  Red  Chalk  of 
Speeton,  in  which  this  Peltastes  was  collected,  the  reader  is  referred  to  page  8  of  this 
Monograph. 

Affinities  and  Differences. — P.  stellulatus  resembles  P.  Wrightii,  but,  according  to 
M.  Cotteau,  the  species  are  quite  distinct.  M.  Cotteau  had  a  large  series  of  the  different 
varieties  of  P.  stellulatus  to  compare  with  specimens  of  P.  Wrightii  from  Farringdon,  sent 
him  by  my  lamented  colleague,  Professor  Edward  Forbes,  and  after  a  careful  study  of 
these  fossils  my  learned  friend  observes,  it  is  true,  that  P.  stellulatus  (var.  punctata) 
closely  resembles  P.  Wrightii,  but  nevertheless  it  is  separated  from  it  by  its  form  being 
more  inflated,  its  tubercles  more  numerous  and  less  prominent,  its  apical  disc  more  smooth, 
less  thick,  and  marked  only  with  some  isolated  points.' 

Locality  and  Stratigraphical  Position. — This  species,  which  is  very  rare  in  England, 
was  collected  from  the  Lower  Greensand  at  Farringdon,  Berks,  and  the  Red  Chalk  at 
Speeton,  near  Filey  Bay,  Yorkshire. 

It  is  abundant,  according  to  M.  Cotteau,  in  France,  in  the  Neocomien  inf.  et  moyen 
at  Saint-Sauveur,  Fontenoy,  Leugny,  Auxerre,  Bernonil,  Tronchoy  (Yonne) ;  Marolles, 
Soulaines  (Aube) ;  Saint-Dizier  (Haute-Marne)  ;  Germigney  (Haute-Saone) ;  Fontanil 
(Isere) ;  Ceuseau,  les  Rousses  (Jura),  where  it  is  abundant ;  and  in  Switzerland, 
according  to  Professor  Desor,  in  the  etage  Valanginien  or  Neocomien  inf.  at  La  Chaux- 
de-Fonds,  Sainte-Croix,  Hauterive,  Lauderon  pres  Neuchatel. 


Peltastes  Lardyi,  Desor.     PI.  XXXI,  fig.  4  a,  b,  c,  d. 

Hyposalenia  Lardyi,  Desor.     Synops.  des  Echinides  Fossiles,  p.  148,  1856. 
Salenia  acupicta,  Desor.  Ibid.,  p.  152. 

Hyposalenia  Lakdyi,  Pictet  et  Benevier.     Foss.  du  terr.  Aptien  de  la  Perte  du  Rhone, 

p.  161,  1858. 
Peltastes  Lardyi,  Cotteau.     Paleontologie   Fran9aise,    terr.  Cretace,  t.   vii,   p.   106, 

pi.  1024,  1862. 

Test  circular,  upper  surface  convex,  under  surface  flat,  sides  inflated,  poriferous  zones 
straight,  ambulacra  narrow,  straight,  two  rows  of  homogenous  mammillated  granules, 
'  'Paleontologie  Fran^aise,  terrain  Cretace,'  t.  vii,  p.  105. 


FROM  THE  LOWER  GREENSAND.  155 

eighteen  in  each.  later-ambulacra  wide,  two  rows  of  tubercles,  five  to  six  in  each,  largest 
at  the  ambitus.  Apical  disc  large,  circular,  with  undulating  borders.  Moutli-opening 
circular,  peristome  decagonal,  vent  transversely  oval. 

Dimensions. — Height  four  tenths  of  an  inch ;  transverse  diameter  eight  tenths  of 
an  inch. 

Description. — This  Salenia,  belonging  to  the  British  Museum,  is  a  very  rare 
form,  and  was  referred  by  my  late  friend  Dr.  Woodward  to  P.  Lardyi.  The  test  is 
circular  with  inflated  sides ;  the  upper  surface  is  convex  and  elevated,  and  the  base  is  flat. 
The  poriferous  zones  are  straight,  formed  of  oval  pores  arranged  in  obUque  pairs ; 
separated  a  small  granule,  and  unigeminal,  throughout,  except  at  the  base,  where  they  are 
a  little  crowded. 

The  ambulacral  areas  are  straight,  with  two  rows-  of  marginal  homogenous,  mani- 
millated,  granules,  eighteen  in  a  row  (fig.  4  c,  d) ;  between  the  rows  there  are  a  double 
series  of  microscope  granulets  filling  in  the  spaces. 

The  inter-ambulacral  areas  are  large,  with  two  rows  of  tubercles,  five  to  six  in 
each  (fig.  4  d),  largest  at  the  ambitus,  diminishing  above  towards  the  disc,  and  below 
towards  the  peristome ;  a  double  row  of  large  mammillated  granules  extends  down  the 
middle  of  the  area,  and  forms  circlets  around  the  tubercles ;  a  large  mammillated 
tubercle  occupies  the  outer  angle  of  each  plate  near  its  union  with  the  poriferous  zones 
(fig.  4  c,  d).  Around  the  base  of  these  granules  a  number  of  small  granulets  are  freely 
distributed ;  the  surface  of  the  test  has  therefore  a  highly  ornamented  appearance. 

The  apical  disc  is  large  and  undulated  at  the  border ;  in  our  specimen  (fig.  4)  the 
sutures  are  much  filled  in,  and  the  typical  character  of  the  species  is  thereby  obscured. 
In  the  beautiful  specimens  from  the  Aptien  of  Auxerre  the  sutures  are  sharply  engraved 
with  isolated  points  and  lines  of  incision,  so  as  to  impart  a  parsley -leaved  character  to  all 
the  elements  of  the  disc.  The  vent  is  moderately  wide  and  transversely  oval,  and  the 
rim  of  the  periprocte  is  a  little  elevated. 

The  mouth-opening  lies  in  a  slight  depression,  it  is  about  half  as  wide  as  the  diameter 
of  the  test.  The  peristome  is  decagonal,  and  marked  by  feeble  incisions ;  of  the  ten 
lobes  those  over  the  ambulacra  are  the  largest. 

Jffinilies  and  Differences. — In  its  form  and  general  characters  P.  Lardyi  approaches 
P.stelhdafus;  it  is,  however,  a  larger  Urchin,  with  its  upper  surface  more  convex  and  inflated, 
sometimes  it  even  assumes  a  sub-conical  shape  ;  the  marginal  rows  of  mammillated 
granules  on  the  ambulacra  are  more  numerous,  and  separated  from  each  other  by  a  double 
series  of  microscopic  granulets  ;  the  apical  disc  is  likewise  thicker  and  more  prominent. 

Locality  and  Stratiyraphical  Position. — Collected  from  the  Sponge-gravel  of  the 
Lower  Greensand,  near  Farringdon,  where  it  was  associated  with  P.  Wrightii.  It  is  a 
very  rare  form  in  the  English  Neocomian  strata.  The  fossil  figured  belongs  to  the 
British  Museum,  and  is  the  only  English  specimen  I  know. 


150  PELTASTES 

B.  Species  from  the  Tipper  Greensand. 
Peltastes  clathratus,  Agassiz.     PL  XXXII,  fig.  1  a—f,  2,  3,  4. 

Parkinson's  Organic  Remains,  vol.  iii,  pi.  i,  fig.  13,  1811. 

Salenia  clathrata,  Agass.  MSS.     Morris's  Catalogue  of  British  Fossils,  p.  58,  1843. 

—  STELLULATA,     Id.  Ibid.  Ibid. 

—  UMBRELLA,       Id.  Ibid.  Ibid. 

—  OENATA,  Id.  Ibid.  Ibid. 

—  CLATHRATA,  Bronti.     Index  Palseontologicus,  p.  1007,  1849. 

UMBRELLA,        Id.  Ibid.,  p.  1008. 

—  CLATHRATA,   Forbes.      In    Morris's   Catalogue  of   British  Fossils,    2nd  ed., 

p.  89,  1854. 

—  STELLULATA,      Id.  Ibid.  Ibid. 

—  UMBRELLA,         Id.  Ibid.  Ibid. 

—  CLATHRATA,    Woodward.       Mem.    of    Geol.  Survey,    App.    to    Decade   V, 

p.  6,   1856, 

—  —  Desor.     Synopsis  des  Echinides  Fossiles,  p.  151,  1856. 
Peltastes  clathratus,   Cotteau.      Faleontologie   Fran9ai8e,  terr.   Cretace,  tome  vii, 

p.  119,  pi.  1028,  fig.  8—18,  1862. 

Diagnosis. — Test  siibglobose  very  convex  above,  poriferous  zones  straight,  ambulacra 
narrow,  straight,  with  two  rows  of  mammillated  granules.  Inter-ambulacra  wide,  three 
pairs  of  prominent  tubercles,  miliaiy  zone  narrow.  Apical  disc  very  large,  covering  nearly 
the  entire  upper  surface,  its  outline  very  deeply  indented  between  the  ovarial  and  ocular 
plates,  which  are  smooth,  and  deeply  notched  at  the  sutures ;  those  connecting  the  centres 
of  the  plates  forming  a  distinct  pentagon,  each  of  the  ovarial  pores  is  the  centre  of  five 
radiating  grooves  with  angular  depressions  between  them. 

Dimensions. — Height  nine  twentieths  of  an  inch ;  six  tenths  of  an  inch. 

Description. — This  Salenia  is  a  very  common  species  in  the  Upper  Greensand  of 
Wiltshire,  where  it  is  often  found  in  a  fine  state  of  preservation.  The  test  in  general  is 
small  and  subglobose,  although  depressed  varieties  sometimes  occur.  It  is  collected 
likewise  from  the  Grey  Chalk  near  Folkestone,  from  whence  the  largest  individuals  have 
been  obtained.  In  the  subglobose  forms  the  upper  surface  is  convex  and  inflated,  and 
the  under  surface  is  flat,  with  rounded  sides  (PL  XXXII,  fig.  1  a).  The  ambulacral 
areas  are  narrow  and  very  slightly  flexed;  two  rows  of  small  mammillated  tubercles, 
fourteen  to  sixteen  in  each,  set  closely  together,  are  placed  on  the  sides  of  the  area  (fig. 
1  d),  and  a  line  of  microscopic  granules  occupies  the  centre,  and  a  few  are  scattered 
between  the  tubercles  (fig.  1  e).  The  poriferous  zones  are  slightly  flexed  (fig.  1  d),  and 
the  holes  lie  in  oblique  pairs  (fig.  1  e)  ;  the  septum  separating  each  pair  has  a  prominent 
elevation ;  and  there  are  eight  [)airs  of  holes  opposite  the  larger  plates. 

The  inter-ambulacral  areas  are  wide,  and  the  plates  in  the  cohimns  unequal  in  size ; 


.      FROM  THE  UPPER  GREENSAND.  157 

there  are  four  or  five  tubercles  in  each  series,  and  of  these  the  two  uppermost  only  attain 
a  considerable  development  (fig.  1  b,  and  fig.  1  d,  and  fig.  3).  The  others  are  much 
smaller,  and  diminish  in  size  as  they  approach  the  peristome  (fig.  1  c  and  fig.  1  d) ;  the 
margin  of  each  plate  is  surrounded  by  a  series  of  small  mammillated  granules  (fig.  1  <?, 
and  fig.  3),  which  form  a  circle  around  the  tubercles,  and  in  the  upper  part  of  the  area 
between  the  larger  granules  a  number  of  smaller  granulets  are  placed  between  tliem 
(fig.  I  d),  thus  completing  the  ornamentation  of  the  miliaiy  zone. 

The  base  of  this  urchin  is  flat,  and  the  mouth-opening  small  (fig.  I  c) ;  the  peristome 
is  divided  into  ten  nearly  equal  lobes,  by  feeble  incisions  (fig.  1/and  fig.  1  c). 

The  apical  disc  is  very  large,  and  occupies  all  the  upper  surface  of  the  test  (fig.  1  b, 
fig.  3).  Its  ovarial  plates  are  deeply  cut,  with  numerous  incisions,  which  are  much  better 
defined  by  figures  than  words ;  faithful  portraits  of  these  most  complicated  impressions 
my  friend  Mr.  Bone  has  given  in  fig.  1  b,  fig.  2,  fig.  3,  and  fig.  4.  These  incisions  are 
large  and  deep,  and  extend  through  the  thickness  of  the  plates ;  three  deep  incisions  mark  the 
line  of  suture  between  the  ocular  and  ovarial  plates  (fig.  2) ;  the  two  antero-lateral  ovarials 
have  another  series  of  impressions  of  a  like  character  before  the  vent  and  behind 
the  oviductal  opening.  The  oviductal  holes  are  large ;  the  two  anterior  are  placed 
forward  on  their  respective  plates ;  the  three  posterior  lie  near  the  inner  borders  of 
the  genital  plates  and  opposite  the  angles  of  the  periprocte.  The  ocular  plates  are  heart- 
shaped,  and  the  orbit  occupies  a  depression  at  the  summit  of  the  ambulacra,  near  the 
extreme  border  of  the  plates.  The  vent  is  large  and  transversely  oblong,  sometimes 
even  becoming  angular  (fig.  1  b).  The  periprocte  is  elevated,  and  its  funnel-shaped 
extremity  encircled  by  a  bourrelet  directed  backwards  (fig.  3).  Most  specimens  show 
this  elevation  of  the  vent,  but  in  many  varieties  it  is  not  so  conspicuous  as  in  the  type 
specimen  figured  in  fig.  3,  where  the  test  is  magnified  twice.  The  spines  are  long  and 
needle-shaped  (PL  XLII,  fig.  4)  ;  above  the  milled  ring  is  a  broad  band  of  longitudinal 
hues,  and  the  rest  of  the  stem  is  covered  with  very  fine  longitudinal  microscopic  lines.  For 
further  details  on  the  spines  of  this  and  other  species,  see  description  of  PL  XLII. 

Affinities  and  Differences. — Peltastes  clathratus  is  readily  distinguished  from  its  con- 
geners by  its  subglobose  test,  the  great  size  of  its  apical  disc,  and  the  number,  width,  and 
depth  of  the  numerous  incisions  that  divide  its  surface  ;  its  flat  base  and  small  mouth 
opening,  with  its  rounded  sides,  present  an  ensemble  of  characters  which  well  characterise 
the  species  and  separate  it  from  all  the  others. 

Locality  and  Stratigraphical  Position. — This  species  was  in  former  years  veiy  common 
in  the  Upper  Greensand  near  Warminster.  Small  examples  were  most  abundant,  and 
large  specimens  were  rare.  The  largest  tests  are  collected  from  the  Grey  Chalk  near 
Folkstone ;  my  kind  friend  the  Rev.  T.  Wiltshire  has  obtained  several  large  examples  from 
this  stratum,  and  several  of  these  have  their  spines  in  situ  on  the  test. 

M.  Cotteau  gives  as  the  French  localities  of  this  species,  -where  it  is  very  rare,  I'fitage 
Cenomanien,  Le  Havre,  Seine-Inferieurc,  La  Perriere,  Orne,  Craie  a  Scaphites. 


158  PELTASTES 


Peltastes  umbrella,  Agassiz,  MSS.     PL  XXXIV,  fig.  1  a — d,  fig.  2  and  3. 

Salenia  umbrella,  Agass.  MSS.    Morris's  Catalogue  of  British  Fossils,  p.  58,  18-13. 

—  —  Id.     Forbes,  in  Morris's  Catal.  of  British  Fossils,  p.  89,  1854. 

—  clatheata,     Id.     Woodward  (pars),  Mem.  of  Geol.  Surv.,  App.  to  Decade  V, 

1856. 

Diagnosis. — Body  subglobose,  convex  above ;  apical  disc  large,  covering  the  upper 
surface,  its  outline  deeply  indented  between  the  ovarial  and  ocular  plates,  sutural  grooves 
deeply  and  sharply  cut,  those  connecting  the  centres  of  the  plates  fomaing  a  distinct  pen- 
tagon. Each  oviductal  hole  forms  a  centre,  from  which  five  grooves  radiate,  having  angular 
pits  between  them ;  sur-anal  plate  marked  with  an  inverted  triangle  formed  by  horizontal 
and  inclined  incisions.  Ambulacra  wide ;  two  rows  of  mammillated  tubercles  crowded 
with  granules  around  the  base  ;  interambulacra  with  four  large  tubercles  in  the  upper  part, 
and  all  the  others  small,  diminishing  towards  the  peristome ;  base  flat,  mouth-opening 
small. 

Dimensions. — Height,  one  quarter  of  an  inch  ;  latitude  half  an  inch. 

Description. — I  have  figured  the  type  specimen  of  this  form  belonging  to  the  British 
Musemn,  as  it  is  the  species  Prof.  Agassiz  gave  this  manuscript  name  to  many  years 
ago,  when  he  examined  the  Cretaceous  Urchins  in  the  National  Collection.  Whether  P, 
umbrella  is  specifically  distinct  from  Peltastes  clathratiis  I  am  not  in  a  position  to  decide. 
The  apical  disc  is  certainly  much  more  angularly  incised,  and  more  sharply  defined  than 
in  P.  dathratm ;  and  placing  two  well  marked  specimens  of  these  type  forms  in  contrast,  the 
decision  would  lie  in  the  affirmative ;  but  then  we  have  the  evidence  of  M.  Cotteau,  who 
informs  us  that  the  incisions  and  impressions  on  the  disc  alone  are  not  to  be  relied  on  as 
specific  characters,  as  one  fonu  glides  into  another  by  a  series  of  intermediate  gradations,  which 
connect  together  fonns  that  appeared  when  isolated  to  be  very  distinct  from  one  another. 

The  ambulacral  areas  are  nearly  straight,  and  have  two  marginal  rows  of  small  mam- 
millated tubercles,  fourteen  in  each.  The  mesial  space  between  the  rows  and  tubercles  is 
filled  with  microscopic  granules  (fig.  1  c).  The  poriferous  zones  are  conspicuous,  and  the 
pores  placed  in  oblique  pairs.  The  inter-ambulacral  areas  are  wide,  and  the  plates  in 
the  columns  unequally  developed,  those  above  the  ambitus  are  the  widest,  and  support 
large  tubercles  ;  from  the  ambitus  to  the  peristome  they  gradually  become  smaller,  and 
their  respective  tubercles  diminish  in  the  same  proportion  (fig.  1  b,  fig.  1  c,  and  fig.  2). 

The  apical  disc  is  large,  and  its  circumference  much  indented  between  the  margin  of 
the  ocular  and  ovarial  plates  (fig.  1  a,  and  fig.  3),  presenting  two  beautiful  varieties  of  this 
remarkable  structure.  The  sur-anal  plate  situated  before  the  periprocte  is  marked  with 
incisions  that  form  a  triangle ;  each  oviductal  hole  of  the  two  antero-lateral  ovarial  plates 
forms  a  centre,  from  which  five  incisions  radiate,  and  from  each  oviductal  hole  in  the  other 
three    ovarial    plates    four    incisions    radiate    outwards,    having   angular   pits    between 


FROM  THE  UPPER  GREENS  AND.  159 

them.  The  vent  is  raised  on  an  eminence  which  is  directed  backwards.  The  anal  opening 
is  transversely  oval,  and  the  periprocte  forms  a  thickened  bourrelet,  which  is  oblong  in  the 
variety  fig.  1  a  and  angular  in  fig.  3.  In  both  figures  the  apical  disc  is  magnified  four 
^diameters. 

The  base  of  the  test  is  flat,  and  the  mouth  opening  small,  about  one  third  the  diameter 
of  the  test.  The  specimens  figured  in  figs.  2  and  3  have  been  kindly  communicated  by 
W.  Cunnington,  Esq.,  F.G.S.,  as  remarkably  well  marked  forms  of  this  species. 

AjfmUies  and  Differences. — The  test  of  P.  umbrella  closely  resembles  that  of  P. 
dathratus,  the  difierence  chiefly  residing  in  the  form  and  structure  of  the  apical  disc,  which 
can  be  much  better  understood  by  a  comparison  of  the  figures  in  PI.  XXXII,  fig.  2,  and  Pi. 
XXXIV,  fig.  1  a,  fig.  1  b,  fig.  1  d,  and  fig.  3,  and  to  which  we  must  beg  to  refer  the 
reader. 

Locality  and  StratigrapMcal  Position. — The  type  specimen  was  collected  from  the 
Upper  Greensand  near  Warminster,  associated  with  Peltastes  dathratus  in  the  same 
stratum. 

Peltastes  Bunburyi,  Forbes,  sp.     PI.  XXXIX,  fig.  2  a — i. 

Salenia  Bunburyi,  Forbes.     In  Morris's  Catalogue  of  British  Fossils,  p.  89,  1854. 
—  —  Woodward.     Mem.  Geol.  Surv.,  App.  to  Decade  V,  p.  6,  1856. 

Diagnosis. — Test  subglobose,  much  elevated,  sides  tumid,  base  wide  and  flat ;  oral 
aperture  depressed ;  apical  disc  large,  very  deeply  indented  at  the  border,  between  the 
ocular  and  ovarial  plates ;  a  series  of  ten  elliptical  ridges  with  central  depressions  fomihig 
an  ornamented  pentagon  on  the  disc;  sur  anal  plate  with  two  pairs  of  oblique  elliptical 
ridges.  Vent  large,  diamond-shaped,  exceutral,  looking  obliquely  backwards,  with  a 
thickened  periprocte.  Ambulacra  narrow,  slightly  flexed,  with  small  remote  marginal 
tubercles,  separated  by  a  prominent  ridge  of  microscopic  granules.  Inter-ambulacra  wide ; 
three  prominent  tubercles  at  the  ambitus,  and  four  smaller  near  the  base  ;  upper  surface 
covered  with  scattered  granules. 

Dimensions. — Height,  half  an  inch  ;  transverse  diameter,  thirteen  twentieths. 

Description. — The  original  and  unique  specimen  of  tliis  Salenia  was  presented  to  the 
Museum  of  the  Royal  School  of  Mines  by  E.  II.  Bunbury,  Esq.,  M.P.  My  late  lamented 
colleague  Professor  Edward  Forbes  named  this  Urchin,  without  leaving  any  notes  of  its 
specific  characters.  A  brief  diagnosis  of  these  were  given  by  my  late  friend  Dr.  Woodward 
in  his  appendix  to  the  fifth  Decade  of  the  Organic  Remains  in  the  Memoirs  of  the 
Geological  Survey.     It  is  now  figured  for  the  first  time. 

The  test  is  svdiglobose  and  much  elevated  (fig.  2  a — d),  inclining  to  a  conical  form. 
The  andjulacral  areas  are  narrow,  and  slightly  flexed  with  two  rows  of  small  remote 
marginal  tubercles,  sixteen  or  seventeen  in  each  row.  These  are  separated  by  a  median 
ridge  formed  of  microscopic  granules,  which  fill  up  all  the  space  unoccupied  by  the  tubercles. 


160  PELTASTES 

The  poriferous  zones  are  naiTow,  the  pores  small  and  placed  in  oblique  pairs,  of  which 
there  are  forty  in  each  zone.  The  septa  between  the  pores  are  capped  by  a  prominent 
granule. 

The  inter-arabulacral  areas  are  wide,  and  the  plates  in  the  columns  of  unequal  size. 
There  are  three  large  tubercles  in  each  area ;  of  these  one  is  very  large,  and  two  mode- 
rately so ;  the  five  others  diminish  gradually  towards  the  peristome ;  the  upper  surface  is 
destitute  of  tubercles,  and  this  vacant  space  is  covered  with  small,  various  sized,  sparsely 
scattered,  niaramillated  tubercles  ;  a  series  of  these  encircle  the  areolas  of  the  primary 
tubercles.  Fig.  2/  represents  an  inter-ambulacral  area,  magnified  four  diameters, 
showing  the  great  disparity  existing  between  the  volume  of  the  different  tubercles  deve- 
loped therein.  The  miliary  zone  is  likewise  ornamented  with  similar  bodies.  Fig.  2  h 
displays  these  parts,  magnified  six  times,  in  a  single  plate,  and  fig.  2  «  a  tubercle  seen 
in  profile. 

The  base  is  wide  and  flat,  and  highly  ornamented  with  the  small  close-set  tubercles 
of  the  inter-ambulacral  areas.  The  oral  aperture,  one  third  the  diameter  of  the  test,  lies 
in  a  depression  (fig.  2  c).     The  peristome  is  divided  into  ten  lobes  by  feeble  incisions. 

The  apical  disc  occupies  a  large  portion  of  the  upper  surface ;  its  border  is  exceed- 
ingly sinuous,  and  deeply  incised  at  the  marginal  boundary  line  between  the  ocular  and 
ovarial  plates ;  from  each  oviductal  hole  two  pairs  of  elliptical-shaped  incisions  proceed, 
and  right  and  left  to  join  those  proceeding  from  the  adjoining  oviduct ;  and  these  form 
the  sides  of  the  pentagon  which  extends  around  the  disc.  The  sur-anal  plate  is  marked 
by  two  pairs  of  elliptical  incisions,  which  join  those  from  the  anterior  ocular,  and  thus 
form  a  diamond-shaped  impression  before  the  vent  (fig.  2  c).  The  ovarial  plates  termi- 
nate in  three-lobed  cardiform  expansions,  and  from  each  side  of  the  orbits  similar  heart- 
shaped  trilobate  bodies  stretch  obliquely  outwards.  The  disc  of  this  species  forms  a 
most  complicated  structure,  of  which  words  fail  to  give  any  adequate  idea.  Fortunately, 
my  friend  Mr.  Bones'  admirable  figures  supply  the  eye  with  the  fine  symmetrical  propor- 
tions of  this  intricate  bit  of  anatomy.     Consult  fig.  2  a,  b,  d,  e,  for  all  details. 

The  vent  is  large  and  looks  obliquely  backwards ;  it  is  of  a  diamond  shape,  with  a 
thick  prominent  periprocte  ;  at  the  three  posterior  angles  of  this  bourrelet  the  single  and 
postero-lateral  oviducts  open,  the  two  antero-laterals  are  placed  much  in  advance  on  the 
lateral  boundary  of  the  sur-anal. 

Affinities  mid  Differences. — The  sculpture  of  the  apical  disc  and  the  deep  incisions 
through  the  same  reminds  us  of  some  forms  of  Peliastes  clathratus ;  the  margin,  however, 
is  more  deeply  indented,  and  the  style  of  ornamentation  on  the  same  is  different ;  the 
marginal  tubercles  on  the  ambulacra  are  smaller  and  more  remote,  and  divided  by  a 
prominent  granulated  ridge ;  the  structure  of  the  inter-ambulacra  exhibits  a  considerable 
diflerence,  and  the  pores  in  the  zones  are  smaller  and  more  numerous. 

Locality  and  Strafip-apMcal  Position. — This  rare  Salenia  was  collected  from  the 
Lower  Chalk,  Mildenhall,  near  Bury  St.  Edmunds.  The  original  and  unique  specimen 
is  in  the  Museum  of  the  Royal  School  of  Mines. 


THE 


PAL/EONTOGRAPHICAL  SOCIETY. 


INSTITUTED  MDCCCXLVII. 


VOLUME    FOE    1872. 


LONDON 

MDCCCLXXII. 


MONOGRAPH 


ON    THE 


BRITISH     FOSSIL 


ECHINODERMATA 


FROM 


THE  CRETACEOUS  FORMATIONS. 


BY 


THOMAS  WRIGHT,  M.D.,  F.R.S.  Edin.,  F.G.S., 

COKKESPONDING    MEMBER  OF    THE    ROYAL   SOCIETY   OF  SCIENCES  OF  LIEGE,   THE   SOCIETY   OF 

NATURAL  SCIENCES    OF   NEUFCHATEL,   AND    SENIOR   SURGEON  TO 

THE    CHELTENHAM    HOSPITAL. 


VOLUME    FIRST. 
PART  FIFTH. 

ON    THE    SALENIDtE. 

Pages  161—184  ;  Plates  XL— XLIV. 


LONDON: 

PRINTED   FOR  THE   PAL^EONTOGRAFHICAL    SOCIETY. 

1872. 


PBINTED  BT 
J.  E.  ADLARD,  BABTHOLOMEW    CLOSE. 


FROM  THE  RED  CHALK.  161 


Peltastes  Wiltshirei,    Wri(jht,  nov.  sp.     PI.  XL,  fig.  1  a — h. 

Biagnosis. — Test  subglobose,  elevated  at  the  upper  surface,  flat  at  the  base  ;  ambulacra 
narrow,  straight,  two  rows  of  marginal  mammillated  granules ;  poriferous  zones  narrow, 
and  slightly  flexed ;  inter-ambulacra  wide,  two  rows  of  large  tubercles,  five  in  each  ;  apical 
disc  very  broad,  margin  deeply  cut  out ;  ovarial  plates  largely  incised ;  vent  elevated  j 
periprocte  prominent,  projecting  outwards  and  backwards. 

Dimensions. — Altitude,  six  tenths  of  an  inch  ;  latitude,  eight  tenths  of  an  inch. 

Description. — We  owe  the  discovery  of  this  beautifid  Peltasfes  to  the  long,  careful,  and 
patient  study  of  my  excellent  friend,  the  Rev.  T.  Wiltshire,  F.G.S.,  on  the  red  chalk  of 
England,  to  whose  valuable  collection  it  belongs.  The  test  is  subglobose,  much  elevated 
on  the  upper  surface,  and  covered  with  a  very  large  apical  disc  ;  the  base  is  flat,  and  the 
sides  are  tumid.  The  ambulacral  areas,  very  narrow  and  straight,  are  occupied  by 
two  rows  of  small  oblong  mammillated  marginal  granules,  about  nineteen  in  each  row, 
separated  by  a  narrow  band  of  fine,  close-set  granulations,  which  extends  from  the  base  to 
the  summit  of  the  area ;  the  poriferous  zones  are  narrow  and  slightly  flexed,  and  the 
small  pores  are  arranged  in  oblique  pairs,  of  which  there  are  thirty-eight  in  each  zone. 
Eig.  l/exhibits  one  entire  ambulacrum,  with  its  poriferous  zones,  magnified  four  diameters. 

The  inter-ambulacral  areas  are  wide  and  largely  developed  (fig.  1  a,  d,  c) ;  the  ovarial 
and  ocular  plates  of  the  apical  disc  cover  up  much  of  the  upper  portion  (fig.  1  b,  d,  e) ; 
there  are  ten  primary  tubercles  in  each  area,  of  which  four  are  very  large,  two  small,  and 
four  smaller ;  they  are  all  surrounded  by  wide  areolas  (fig.  1  d,  e),  and  around  their 
margins  a  few  large  granules  are  sparsely  disposed,  about  five  around  the  largest  plates, 
three  at  the  central,  and  two  at  the  zonal  side  of  the  plate,  as  shown  in  fig.  1  h.  The 
base  is  flat  (fig.  1  c),  about  two  fifths  the  diameter  of  the  disc,  the  mouth-opening  is 
nearly  one  half  the  diameter  of  the  test,  and  the  peristome  is  divided  into  ten  nearly 
equal  lobes  by  deep  incisions ;  the  numerous  small  tubercles  at  the  base  of  the  areas,  and 
the  larger  size  of  the  marginal  ambulacral  granules,  impart  to  this  region  of  the  test  a 
highly  ornamented  appearance  (fig.  1  c). 

The  apical  disc  (fig.  1  b  and ^7)  is  a  large  and  complicated  structure  ;  the  suranal  plate  lies 
in  front  of  the  vent,  and  is  notched  with  sections  of  four  elliptical  impressions ;  the  ovarial 
plates  are  large  and  cut  in  a  hke  manner  into  similar  patterns,  the  two  adjoining  plates 
contributing  each  one  half  of  the  ellipse,  so  that  the  sculptured  pattern  on  the  entire  disc 
is  made  up  of  separate  pieces  like  mosaic ;  the  oviductal  holes  are  in  the  middle  of  the 
plates  and  on  the  right  antero-lateral ;  the  madreporiform  tubercle  appears  like  a  laceration 
on  the  inner  side  of  the  oviductal  hole — this  has  unfortunately  escaped  the  eye  of  our 
artist,  as  it  looks  more  like  a  portion  of  decayed  plate  than  a  veritable  natural  structure. 
The  ocular  plates  are  likewise  large,  and  have  five  or  six  notches  round  their  border,  which 
in  like  manner  join  similar  notches  on  the  ovarial  plates  and  complete  the  elliptical  pattern 

21 


162  PELTASTES 

of  the  sculpture  of  the  disc ;  the  outer  border  of  each  ocular  plate  forms  a  crescent  around 
the  summit  of  the  ambulacra,  and  the  terminal  portions  of  the  ovarial  plates  form  an  elegant 
five-leafed  petal  extending  down  the  middle  of  the  inter-ambulacra ;  the  outer  margin 
of  the  disc  is  therefore  very  deeply  incised  between  the  ovarial  and  ocular  plates,  and 
produces  a  structure  which  will  be  better  understood  by  an  examination  of  fig.  1  g,  mag- 
nified four  diameters,  than  by  any  verbal  description.  The  vent  is  large  and  the  periprocte 
bluntly  diagonal,  angular  at  the  sides,  and  less  convex  before  than  behind  (fig.  1  g) ;  when 
viewed  in  profile,  as  in  fig.  1  a  and  d,  the  apical  disc  is  conspicuously  prominent,  and  the 
elevated  periprocte  is  seen  to  be  very  excentral  and  projected  far  backwards. 

Afinities  and  Differences. — This  beautiful  species  in  its  general  characters  resembles 
Scdenia  Austeni,  Forbes ;  but  a  careful  comparison  of  the  tests  of  both  species  discloses 
important  differences ;  the  ambulacra  in  P.  Wiltshirei  are  narrower,  with  only  two  rows  of 
oblong  marginal  granules  throughout,  whilst  S.  Austeni  has  four  rows  in  its  wider 
ambulacra.  The  inter-ambulacral  areas  in  P.  Wiltshirei  are  wider,  and  the  primary 
tubercles  therein  fewer  and  larger  than  in  S.  Austeni.  The  apical  disc  of  P.  Wiltshirei 
is  much  larger  ;  the  marginal  incisions  are  deeper,  the  lines  of  sculpture  wider,  and  the 
periprocte  is  in  the  axis  of  the  suranal  plate. 

This  species  resembles  P.  Bunbiiryi,  Forb.,  in  the  general  structure  of  the  test,  and  of 
the  apical  disc ;  the  inter-ambulacral  areas  in  P.  Wiltshirei  are  wider,  the  tubercles  are 
larger  and  more  regular,  the  apical  disc  covers  a  wider  surface  of  the  test  than  in  P. 
Bunburgi,  and  is  deeply  sculptured  after  a  different  pattern,  both  around  the  margin  and 
along  the  sutures  of  the  plates. 

Locality  and Stratigraphical Position. — llhi?,  Peltastes  is  a  very  rare  Urchin  in  the  Red 
Chalk  of  Hunstanton  Cliff,  Norfolk,  where  it  was  found  by  the  Rev.  T.  Wiltshire,  F.G.S., 
who  has  contributed  a  valuable  paper  on  this  stratum  to  the  '  Quarterly  Journal  of  the 
Geological  Society,'^  and  from  which  I  have  made  the  following  quotations,  as  the  true 
position  of  the  Red  Chalk  is  well  defined  in  that  communication.  1  am  indebted  to  the 
kindness  of  the  Council  of  the  Geological  Society  for  the  use  of  the  annexed  woodcut 
illustrating  the  stratigraphy  of  this  locality. 

Hunstanton  Cliff  "  is  marked  by  three  parallel  coloured  bands,  slightly  inclined,  and 
cropping  out  in  succession  on  the  surface  soil,  of  which  bands  the  uppermost  is  white,  the 
next  bright  red,  and  the  lowest  yellow,  each  division  being  sharply  defined,  without  any 
intermingling  of  tints  at  the  line  of  contact.  .  .  .  The  highest  stratum,  the  white,  con- 
sists of  a  hard  calcareous  substance,  compact  in  texture,  and  much  shattered  and  fissured, 
originally  deposited  in  such  a  manner  that  its  materials  were  arranged  in  definite  layers, 
two  of  which  {a  b),  those  forming  the  base,  are  represented  in  the  annexed  section  drawn 
to  scale.  The  first  of  these  (a),  in  thickness  about  2  feet  6  inches,  is  noticeable  for  the 
presence  of  an  enormous  quantity  of  fragments  of  Inocerami  dispersed  throughout  its 

'  'Quart.  Journ.  Geol.  Soc.,'  vol.  xxv,  p.  185,  1869. 


FROM  THE  RED  CHALK. 


163 


Section  of  Hunstanton  Cliff. 


whole  extent,  and  which  under  the  influence  of  weathering  impart  to  this  portion  of  the 
diff  a  jagged  and  rough  appearance.  Its  characteristic  fossils  are  spines  of  Cidaris  vesi- 
culosa, Holaster  planus,  Vermicularia  umbonata,  Tere- 
bratulina  gracilis,  Terebratula  semiglobosa,  and  Plica- 
tula  inflata.  The  band  h,  in  thickness  about  1  foot  2 
inches,  is  conspicuous  for  a  meandering  and  many- 
branched  Sponge  {Syphonia  paradoxica),  specimens  of 
which  are  visible  in  the  cliff  only  in  short  lengths,  but 
on  the  fallen  blocks  washed  by  the  sea  are  seen  to 
extend  continuously  and  horizontally  over  many  square 
feet  of  surface.  The  underside  of  b  departs  from  the 
general  arrangement  in  the  other  courses ;  for  its  base, 
instead  of  forming  a  flat  or  approximately  flat  floor,  is 
broken  up  into  a  series  of  irregularly  rounded  ridges 
and  hollows,  which  undulate  perpendicularly  within  the 
limits  of  a  few  inches,  and  are  represented  in  the  section. 
The  fossils  from  this  bed  {b)  are  not  so  many  (numeri- 
cally speaking)  as  those  in  a.  The  chief  forms  are 
8ipho)iia  paradoxica,  Terebrafida  biplicata,  Terebratula 
semifflobosa,'^av.  undata,  Kingena  lima,  Avicula grgphmoides, 
and  Inoceramus  latus. 

"  Next  in  succession,  in  descending  order,  is  the  red 
stratum,  locally  called  the  'Red  Chalk,'  marked  by  an 
abundance  of  organic  remains,  some  of  Avhich,  as 
Bourgiieficrinus  rugosus  and  Terebratula  cupillata,  are, 
in  England,  special  to  this  deposit.  Lithologically  it 
is  unlike  the  beds  above  it,  from  the  fact  of  its  abound- 
ing in  great  numbers  of  rolled  and  subangular  pebbles 
of  quartz,  slate,  &c.,  which  for  the  most  part  are  of  small 
size  and  insignificant,  though  occasionally  assuming 
larger  dimensions.  In  appearance  it  is  divisible  into 
three  almost  equal  portions,  of  which  the  first  (a)  has  towards  its  base  a  large 
quantity  of  fragments  of  Inocerami,  the  second  and  thickest  division  (b)  is  rich  in 
Belemnites,  and  the  third  and  lowest  (c)  yields  many  Terebratulce.  The  bands  a  and  b 
are  exceedingly  hard  and  stony,  and  sufficiently  tabular  in  character  to  have  off'ered  a 
plane  of  resistance  to  former  upheaving  forces,  and  to  have  aff'orded  great  support  to  the 
overlying  white  beds  ;  thus,  although  the  whole  cliff  was  evidently,  in  ancient  geological 
times,  much  disturbed,  the  perpendicular  fissures  which  rise  out  of  the  yellow  bands 


*  A  thickness  of  upwards  of  30  feet  is  here  omitted  for  convenience. 


164  PELTASTES 

(y,  x)  cease  just  before  reaching  the  layer  b,  affect  the  i^ed  beds  to  the  right  and  left  of 
the  points  of  application,  and  then  start  upwards  through  the  white  stratum  in  new  posi- 
tions and  in  greater  number.  The  colouring  matter  in  a  is  less  equally  distributed  than 
in  B  and  c,  and  seems  to  have  been  accumulated  as  an  envelope  around  irregular  spheroidal 
masses  ;  in  b  the  tint  is  of  a  lighter,  and  in  c  of  a  darker  shade  than  in  the  highest 
division.  The  middle  bed  (b)  is  in  substance  the  hardest  and  most  homogeneous  of  the 
three ;  the  last  (c)  is  the  least  compact.  Viewed  in  the  cliff,  a  wears  a  mottled  aspect,  b 
a  nodular  facies,  and  c  a  plain  surface.  Towards  the  base  of  the  bottom  bed  (c)  the  hard 
limestone  character  of  the  Red  Chalk  is  lost,  and  the  stratum  degenerates  into  a  some- 
what sandy  incoherent  mass,  hardly  differing  from  the  underlying,  yellow  division,  except 
in  colour.  On  account  of  the  less  compact  nature  of  the  last  of  the  three  red  beds,  fossils 
are  more  easily  procured  from  it,  have  their  surfaces  in  better  condition,  and  are  more 
readily  seen  when  of  small  size.  Resting  on  the  top  of  a  and  filling  the  undulations  on 
the  under  side  of  the  lowest  white  bed  {d)  is  a  bright  red  argillaceous  substance,  very 
friable,  without  sand,  apparently  destitute  of  organic  remains,  and  never  exceeding  two 
or  three  inches  in  thickness. 

"  The  fossils  in  the  three  red  beds  are  for  the  most  part  similar,  and  suggest  the  infer- 
ence that  all  three  bands  may  be  considered  as  forming  a  single  division,  and  composing 
one  geological  stratum.  In  the  case  where  certain  fossils  have  been  seen  only  in  the 
lowest  part,  their  absence  elsewhere  may  be  accounted  for  on  the  ground  that  the  upper 
bed  (a)  is  less  numerically  abundant  in  organic  remains  than  are  those  below,  and  that 
the  middle  bed  (b)  is  so  exceedingly  hard  and  compact  as  to  diminish  the  chance  of 
discovering  fossds.  Avicida  (jrypliaoides  and  Spongia  jjcradoxica  would  seem,  however, 
to  be  special  to  the  upper  part  of  a,  the  highest  of  the  three  red  beds.  The  dip  of  these 
beds  in  the  cliff  is  about  2°  to  the  north ;  sections  inland,  taken  at  right  angles,  give  the 
same  number  of  degrees  to  the  east. 

"  Underlying  the  Red  Chalk  is  a  coarse  sandy  deposit  (x,  t  of  the  Section)  termed 
in  the  district  '  Carstone,'  of  a  yellow  tint,  loose  in  composition,  and  full  of  small  pebbles, 
which  are  subangular  and  polished.  The  upper  part  (x),  for  about  8  feet,  consists  of 
much  sand,  and  is  succeeded  by  a  dark  brown  stratum  (y),  in  which,  at  the  beginning, 
the  pebbles  are  of  larger  size,  and  in  which,  afterwards,  the  sandy  particles  are  so 
loosely  held  together  as  to  present  a  strong  contrast  to  the  massive  nature  of  the  white 
and  red  beds  above.  Covered  by  the  Carstone  and  adjoining  it  is  a  bed  of  clay  marked 
z  in  the  section. 

"  Throughout  the  space  of  more  than  thirty  feet  below  the  base  of  the  Red  Chalk  no 
fossils  have  been  hitherto  found  at  Hunstanton  in  the  Carstone;  but  beyond  that  distance, 
and  just  above  the  clay  (z),  there  is  a  line  of  nodules  (j/),  in  which  are  numerous  speci- 
mens oi  Ammonites  Deshayesi,  and  occasionally  of  ^.  Cornuelianus ;  close  to  these  nodules 
are  others  of  ironstone,  very  similar  to  the  masses  found  in  the  Lower  Greensand  of 
Blackgang  and  Shanklin,  in  the  Isle  of  Wight,  containing  casts  of  fossils. 


FROM  THE  RED  CHALK.  16£ 

"  From  this  part  of  the  Carstone  I  have  obtained  Perna  Mulleti,  Ancyloceras  (jigas, 
Pleuroiomaria  gigantea — fossils  which,  viewed  in  connection  with  the  presence  of  Ammo- 
nites Deshayesi,  &c.,  correlate  the  portion  of  the  Carstone  iuamediately  above  the  clay  (z) 
with  the  base  of  the  English  Lower  Greeusand. 

"  By  a  reference  to  the  section  it  will  be  seen  that  the  Hunstanton  Red  Chalk  is,  in 
position,  lower  than  the  Chalk-marl  («),  and  higher  than  the  Lower  Greensand  (x,  y)  ; 
the  fossils  also,  it  will  be  observed,  recorded  in  the  list  as  common  to  the  bed,  present  a 
mixture  of  what  are  generally  considered  Lower  Chalk,  Upper  Greensand,  and  Gault 
forms.  The  mingling  together  of  these  species,  no  less  than  the  peculiar  aspect  of  the 
stratum,  has  long  caused  the  Red  Chalk  to  be  a  fertile  field  for  discussion  in  reference  to 
its  proper  position  in  the  geological  scale,  various  writers  ofiering  various  opinions,  Mr, 
C.  B.  Rose^  inclining  to  its  being  the  equivalent  of  the  Gault,  Mr.  H.  Seeley"  to  its  being 
Upper  Greensand,  and  Mr.  Judd'  to  its  combining  both  formations.  If,  however,  the 
very  fine  section  of  the  Gault  at  Folkstone  (where  the  succession  of  the  beds  and  their 
fossils  can  be  examined  in  situ)  be  taken  as  typical  of  the  English  Gault,  then  it  will 
become  evident  that  the  '  Red  Chalk '  is  the  representative  of  the  upper  division  of  that 
formation." 


Genus — Goniophorus,  Jgassiz,  1838. 
GoNioPHORUs,  Desor.  Goniophorus,  Cotteuu. 

Test  small,  circular,  elevated  above,  and  flat  beneath.  Interambulacral  areas  wide,  two 
rows  of  large  tubercles  with  well-developed  areolae,  crenulated  bosses  and  imperforate 
mammelons ;  pores  small,  simple,  unigeminal.  Ambulacral  areas  very  narrow,  and  having 
the  poriferous  zones  slightly  undulated. 

jMouth-opening  small,  peristome  decagonal,  with  nearly  equal  sized  oral  lobes. 

Apical  disc  smooth,  prominent,  regularly  pentagonal,  and  moderately  large,  composed 
of  five  ovarial  and  five  ocular  plates,  and  one  suranal  placed  before  the  vent,  which  is 
excentral,  in  the  axis  of  the  body,  and  placed  a  little  backwards,  as  m  the  genus  Peltastes. 
The  disc  is  destitute  of  sutural  impressions  so  characteristic  of  many  Salenid^,  and  is 
ornamented  with  prominent  carinse,  which  assume  regular  geometrical  figures,  altogether 
independent  of  the  form  of  the  ovarial  plates  or  their  connecting  sutures ;  in  fact,  it  is 

'   "On  the  Geology  of  West  Norfolk,"  '  Phil.  Mag.,'  1835,  vol.  vii,  p.  180. 

-  "Notice  of  Opiuions  ou  the  Stratigraphical  Position  of  the  Red  Limestone,"  'Ann.  Mag.  Nat.  Hist.,' 
1861,  vol.  vii,  p.  240. 

3  "Strata  which  form  the  base  of  the  Lincolnshire  Wolds,"  'Quart.  Journ.  Geo).  Soc.,' vol.  xxii, 
p.  249,  1867. 


166  GONIOPIIORUS 

the  carinated  structure,  superadded  to  the  surface  of  the  disc,  which  forms  one  of  the  most 
distinctive  characters  of  this  group. 

The  genus  Goniophorus  resembles  Peltnstes  in  the  arrangement  of  the  elements  of  the 
apical  disc  and  the  relative  position  of  the  periprocte  to  the  axis  of  the  body.  It  is  distin- 
guished from  it,  however,  in  the  absence  of  sutural  impressions,  and  the  presence  of 
prominent  ribs,  that  divide  the  smface  of  the  pentagonal  disc  into  a  number  of 
triangular  areas  (PI.  XXXVI,  figs.  1  and  2). 

M.  Cotteau^  has  added  another  character,  which  he  considers  of  more  importance  than 
the  preceding ;  and  observes,  "  The  structure  of  the  ambulacra  presents  a  difference 
much  more  important,  and  the  existence  of  poriferous  impressions  at  the  base  of  some  of 
its  granules  form  a  type  certainly  exceptional,  which  ought  to  have  a  place  apart  in  the 
Family  Salenid.^.     This  character  has  not  hitherto  been  noticed  in  any  other  Echinid." 


Goniophorus  lunulatus,  Jf/assiz,  183S.     PI.  XXXVI,  fig.  1  a — d,  fig.  2  a — d. 

GoNioPHORts  LLXULATUS,     Affitssh.  Monogr.  des  Salenies,  p.  30,  pi.  v,  figs.  1" — 2-1, 

1838. 

—  APICUL.VTUS,    Agassi-.     Ibid.,  p.  32,  pi.  v,  figs.  25 — 32,  1838. 

—  —  Jgassiz.     Catal.  Ectyp.  Foss.,  p.  ii,  1840. 

—  FAVOSUS,  Agassi:,  MS.     Morris's   Catal.    of  British    Fossils,  p.   52, 

1843. 

—  LUNULATUS,     Morris.     Catalogue  of  British  Fossils,  p.  52,  1843. 

—  —  Agassis  et  Besor.     Catal.  raison.  des  Ecliiiiides,  Aim.  des 

Sc.  Nat.,  3e  serie,  t.  vi,  p.  343,  1846. 

—  APICULATUS,    Agassi:  et  Besor.     Ibid. 

—  —  Bronn.     Index  Paleeontol.,  p.  548,  1849. 

—  FAVOSUS,  Biohii.     Ibid. 

—  LUNULATUS,     Bronn.     Ibid. 

—  —  B'Orbigmj.     Prod,  de  Pal.  strat.,  t.  ii,  p.  179,  1850. 

—  APICULATUS,     B'Orbigmj.     Ibid. 

—  F.Yvoscs,         B'Archiac.     Hist,  des  Progr.  de  la  GeoL,  t.  iv,  p.  51,  1851. 

—  LUNULATUS,     Bromi.     Lethsea  geogn.,  t.  ii,  p.  184,  pi.  xxix,  fig.  6,  1852. 
Salenia  lunulata,  Morris.     Catal.  of  Brit.  Foss.,  2  ed.,  p.  89,  1854. 
GoNioPHOKUs  APicuL.^TUs,  Besur.      Synopsis   des   Echinides   Foss.,   p.    14,    pi.    xx, 

fig.  12,  1856. 

—  LUNULATUS,     Pictet.     Traite  de  Paleontol.,  t.  iv,  p.  248,  1857. 

—  APICULATUS,    Pictet.     Ibid.,  pi.  xcvii,  fig.  3,  1857. 

—  LUNULATUS,      Cotteau.     Paleontol.  FranCj-aise,  t.  vii,  pi.  1029,  figs.  8— 19, 

1864. 


'  '  Pak'oiitologie  Frangaise,'  t.  vii,  p.  1'26,  Terrain  cretace. 


FROM  THE  UPPER  GREENSAND.  ~  167 

Diapwsis.- — Test  small,  globular,  upper  surface  elevated,  summit  depressed,  base  flat, 
sides  rounded  ;  ambulacra  narrow,  slightly  flexed,  filled  with  two  rows  of  granules  ;  inter- 
ambulacra  wide,  two  rows,  six  in  each,  of  weU-developed  tubercles  ;  apical  disc  small, 
angular,  and  pentagonal ;  diagonal  ridges  of  shell  marking  the  surface  of  the  plates  ;  base 
narrow,  concave ;  mouth-opening  small,  peristome  decagonal  with  equal  lobes. 

Dimensions.- — -a.  The  largest  specimen,  fig.  \a,  altitude  half  an  inch;  latitude  six 
tenths  of  an  inch. 

B.  Altitude,  three  lines ;  latitude,  five  lines. 

c.  Altitude,  two  and  a  half  lines ;  latitude,  three  and  a  half  lines. 

Description. — This  beautiful  little  Urchin,  the  sole  representative  of  the  genus 
Goniophori/s,  was  at  one  time  not  uncommon  in  the  Upper  Greensand,  near  Warminster, 
and  it  is  curious  that  no  second  species  of  the  remarkable  group  to  which  it  belongs  has 
up  to  the  present  time  been  discovered  ;  the  two  other  forms  which  appear  in  the  table 
of  synonyms  {G.  apiculatiis,  G.  favosus)  being  only  usual  varieties  of  the  original  type, 
so  beautifully  and  accurately  figured  by  M.  Nicolet  in  Professor  Agassiz's  '  Monographies 
d'Bchinodermes,'  where  it  was  for  the  first  time  described. 

The  test  is  small  and  nearly  globular,  the  upper  surface  much  elevated,  the  summit 
a  little  depressed,  the  sides  inflated,  and  the  base  narrow  and  flat.  The  ambulacral 
areas  are  very  contracted,  and  slightly  flexed  (fig.  2  b),  the  two  rows  of  granules  are  set  so 
closely  together  that  they  alternate  on  the  area ;  the  poriferous  zones  are  nearly  as  wide  as 
the  ambulacra,  the  pores  are  oblique,  and  the  pairs  remote  from  each  other,  twenty-four  in 
the  zone.  The  inter-ambulacral  areas  are  well  developed  (fig.  2  a) ;  in  the  specimen,  fig. 
1  a,  there  are  six  primary  tubercles  in  each  row,  the  four  above  the  ambitus  are  much 
larger  than  those  on  the  lower  part  of  the  area,  and  the  areola  of  each  tubercle  is  sur- 
rounded by  a  complete  circle  of  small  mamraillated  tubercles  (fig.  1  a,  d,  and  fig.  %  a,  c)  ; 
the  miliary  zone  separating  the  two  series  is  narrow  and  zig-zag,  and  only  a  little 
enlarged  at  the  upper  surface  (fig.  1  d,  fig.  2  a). 

The  base  is  narrow  and  concave,  and  the  small  mouth-opening,  one  third  the  diameter 
of  the  test,  lies  in  a  central  depression  ;  the  peristome  is  divided  by  feeble  incisions  into  ten 
equal-sized  lobes  (fig.  1  c). 

The  apical  disc  (fig.  1  b,  d)  forms  a  regular  pentagon,  ornamented  with  prominent 
ridges  ;  an  external  carina  bounds  the  outline  of  the  disc,  an  oval  carina  encircles  the  vent, 
and  two  others  extend  from  the  anterior  part  of  the  periprocte  to  the  two  anterior  sides  of 
the  discal  pentagon  (fig.  2  d),  and  two  others  unite  these  with  the  sides  of  the  vent  (fig.  1  b) ; 
these  ridges  of  ornamentation  have  nothing  whatever  to  do  with  the  sutures  of  the  disc, 
which  are  very  delicate,  and  only  seen  in  some  rare  specimens ;  these  sutures  in  Gonio- 
phorus  are  destitute  of  the  incisions,  punctuations,  and  impressions  which  form  so 
remarkable  a  feature  in  the  test  of  Peltastes. 

The  suranal  plate  lies  before  the  periprocte,  having  the  two  anterior  carinse  passing 
from  the  periprocte  to  the  anterior  border  extended  over  its  surface ;  the  two  antero-lateral 


168  GONIOPHORUS 

ovarials  have  a  rliomboidal  figure,  the  postero-laterals  an  irregular  shape,  occasioned 
by  the  lateral  extension  of  the  vent,  and  the  single  plate  is  still  longer  and  narrower  by 
reason  of  the  space  occupied  by  the  same  aperture  ;  the  oviductal  holes  occupy  the  centres 
of  the  sides  of  the  pentagon  near  the  point  touched  by  the  diagonal  carinse  that  cross  the 
ovarial  plates.  The  ocular  plates  form  small  triangular  bodies,  the  apices  of  which  touch 
the  summits  of  the  ambulacra  (fig.  2  b) ;  in  neither  of  the  fine  specimens  from  Mr. 
Cunningham's  collection,  nor  in  those  from  the  School  of  Mines,  which  were  selected  as  the 
best  extant  for  figuring,  could  the  sutures  of  the  ovarial  and  ocular  plates  be  seen.  I  have 
only  discovered  them  now,  April,  1871,  long  after  the  drawings  were  executed.in  an  otherwise 
indifferent  specimen  of  my  own,  collected  many  years  ago,  and  I  have  been  able  therefrom 
to  trace  out  these  sutural  lines  satisfactorily,  and  complete  my  description  of  the  apical 
disc  of  this  most  curious  and  beautiful  Salenia.  The  vent  is  transversely  oblong,  inclining 
to  an  angular  figure,  and  surrounded  by  a  ridge  of  the  test,  which  well  defines  its 
boundary,  and  forms  a  prominent  periprocte  at  the  same  time.  The  carinse  of  the  disc 
cross  the  sutures  of  the  plates  in  all  directions,  especially  those  anterior  to  the  periprocte, 
and  convert  its  surface  into  a  series  of  seven  triangles  when  all  the  ridges  are  preserved 
entire. 

Affinities  and  Differences. — This  Urchin  is  so  entirely  different  from  other  Salenid^ 
in  the  structure  of  its  apical  disc  that  it  forms  a  type  quite  distinct  from  all  the  others  ; 
the  calcareous  processes  or  carinse  on  the  surface  of  the  ovarial  and  ocular  i)lates  have 
nothing  whatever  to  do  with  the  sutural  fines  which  unite  the  elements  of  the  discal 
apparatus,  whereas  in  Peltastes  and  Salenia  the  figures  on  the  disc  are  always  developed 
in  the  line  of  the  sutures. 

Locality  and  Stratigrapldcal  Position. — This  Urchin  has  been  collected  from  the 
Upper  Greensand  near  Warminster;  on  the  Continent  it  is  a  very  rare  fossil.  The 
original  specimen  was  found  in  the  Etage  Cenomanien,  at  Cap  la  Heve,  near  Havre,  Seine 
Inferieure  ;  others  from  the  same  stratum  at  Vaches  Noires,  Calvados,  and  Vimoutiers, 
Orne  ;   in  all  these  localities  it  is  reported  as  being  very  rare. 

History.— Yix%i  described  and  figured  by  Professor  Agassiz  in  his  '  Monographic  sur 
les  Salenies.'  In  this  work  he  described  two  forms  as  distinct  species,  G.  lunulatus 
and  G.  apicidatiis,  which  I  consider  as  varieties  only  of  the  same  Urchin.  Professor 
Agassiz  afterwards  gave  the  MS.  name  G.  favosus  to  a  form  of  this  group  which 
he  saw  in  the  collection  of  Mr.  Bunbury,  of  London,  and  the  name  found  its  way  into 
Professor  Morris's  '  Catalogue  of  British  Fossils,'  1  st  Edition ;  this  variety  exhibits  only 
a  slight  deviation  from  the  type  form,  so  that  the  singular  genus  GoniojAorus  is  at 
present  represented  by  the  beautiful  little  Urchin  now  under  consideration.  Seeino- 
that  so  many  examples  of  Salenid.e  have  been  collected  from  the  Upper  Greensand  of 
England,  and  the  Cenoraanian  stage  of  France,  during  the  last  forty  years,  it  is  remarkable 
that  no  true  second  species  has  been  found.  It  has  often  occurred  to  me  that  this  is 
one  of  many  problems  of  a  like  nature  that  the  disciples  of  Darwin  might  attempt  to 


FROM  THE  UPPER  GREENSAND.  169 

solve.  The  geological  record  of  the  Cretaceous  rocks  where  the  Salenid^  ■  abound 
is  not  so  imperfect  as  many  assert,  and  connecting  forms,  if  such  ever  really  existed, 
ought  to  be  found  somewhere  in  beds  that  are  so  often  searched  and  so  diligently  worked 
for  the  Palgeontological  treasures  they  contain.  Notwithstanding  all  this  investigation, 
Goniopliorus  lunulatus  still  remains  an  isolated  genus  represented  by  a  single  species 
among  the  Salenid^. 


Genus — Salenia,   Gray,  1835. 
Salekia,  Affassiz,  1838.     Salenia,  Desor,  1858.     Salenia,  Cotteau,  1864. 

Test  small,  circular,  moderately  elevated,  sides  inflated,  more  or  less  convex  above  and 
flat  beneath  ;  poriferous  zones  narrow,  pores  unigeminal,  simple  in  the  zones,  and  crowded 
near  the  peristome ;  ambulacral  areas  narrow,  gently  flexuous,  with  two  or  four  rows  of 
close-set  homogeneous  mammillated  granules.  Inter-ambulacral  areas  wide,  with  two 
rows  of  large  crenulated  imperforate  tubercles. 

Mouth-opening  nearly  two  thirds  the  diameter  of  the  test ;  peristome  divided  into  ten 
unequal  lobes  by  feeble  incisions ;  vent  circular,  periprocte  elevated,  excentral,  and 
posterior,  placed  at  the  right  side  of  the  axial  line  of  the  body ;  apical  disc  shield-shaped, 
covering  a  large  portion  of  the  dorsal  surface ;  plates  prominent,  with  a  deeply  undulated 
border ;  the  ovarials  and  suranal  large  and  pentagonal,  the  ocidars  wide  and  cordate  ;  the 
sutures  punctuated  or  incised,  and  the  surface  of  the  plates  smooth  in  S.  pefal/fera, 
sometimes  granulated,  in  S.  granulosa,  or  striated  with  geometrical  lines  forming  various 
figures,  as  in  8.  Clarkii  and  S.  Austeni. 

The  right  antero-lateral  ovarial  plate  exhibits  a  slight  laceration,  in  which  the  madre- 
poriform  body  is  sometimes  seen  in  ^v•ell-preserved  specimens ;  often  it  is  iuvisible. 

The  spines  are  known  only  in  a  few  species ;  in  some  they  are  long,  slender,  and 
aciculate ;  in  others  they  are  stronger,  with  spatulate  terminations  (PI.  XXXVIII,  fig.  2) ; 
some  rarer  specimens  have  their  stems  flexed,  and  others  have  the  extremities  bent  to  right 
angles  with  the  stem  (PL  XXXVIII,  fig.  3 ;  PI.  XLII,  figs.  1,  2,  3,  4,  5). 

The  genus  Salenia  is  distinguished  from  Heterosalenia  and  Pseudosalenia  by  its 
imperforate  tubercles,  and  from  Pel  tastes,  which  it  very  much  resembles,  by  the  position 
of  the  vent.  In  Salenia  the  periprocte  opens  excentrically  on  the  right  side  of  a  line  passing 
through  the  axis  of  the  body,  whilst  in  Peltastes  the  periprocte  lies  in  the  centre  of  such 
an  axial  prolongation. 


22 


170 


SALENIA 


A. — Species  from  the  Uiiper  Greensand. 
Salenia  PETALiFERA,  Desviarest,  sp.,  1825.     PI.  XXXIII;  PI.  XLII,  fig.  3. 


EcHlNlTE,  from  Wiltshire,  Parkinson.     Organic  Remains,  vol.  iii,  pi.  i,  fin;.  12,  181  I. 


Echinus, 


AREOLATUS, 
PETALIFERUS, 


Salenia  petalifera, 


PERSONATA, 


PETALIFERA, 
PERSONATA, 


—  PETALIFERA, 

PERSONATA, 

—  PETALIFERA, 

—  PERSONATA, 

PETALIFERA, 


JV.  Smith.      Strata  identified   by    Organized   Fossils,  p.    1 2, 

Greensand,  fig.  ii,  1816. 
Koniy.     Icones  foss.  sectiles,  fig.  100,  1820. 
Besmarest.     Oursin  ;   Diet.  Sc.  Nat.,  t.  xx.'cvii,  p.  101,  1825. 
Be  Blainville.     Zoophytes,  Ibid.,  t.  It,  p.  210,  1830. 
Desmoiilins.     Etndes  sur  les  Echinides,  p.  302,  1837. 
Agassi:.     Monogr.  des  Salenies,  p.  9,  pi.  i,  figs.  1 7 — 2-1,  1838. 
Agassiz.     Catal.  Ectyp.  foss.,  p.  II,  1840. 
Bujardin.     [n  Lamarck's  Animau.t  sans  Vert.,  2e  ed.,  t.  iii, 

p.  394,  1840. 
Morris.     Catalogue  of  British  Fossils,  p.  58,  1843. 
Agassi:  et  Besor.     Catal.  rais.  des  Echinides,  .\n\^.  Sc.  Nat., 

3e  serie,  t.  vi,  p.  341,  184G. 
Forbes.     Jlem.  of  Geol.  Surv.,  Decade  I,  pi.  v,  1849. 
Bronn.     Index  Palaeontologicus,  p.  1107,  1849. 
d'Orbigny.     Prodrome  de  Pal.  strat.,  t.  ii,  p.  179,  1850. 
d'Orhujny.     Cours  element,  de  Pal.,  t.  ii,  p.  126,  fig.  277, 

1851. 
Bronn.     Lethsea  Geog.  Kreide-Geb.,  pi.  xxix,  fig.  15,  1852. 
John  Mailer.     TJeber  den  Bau  der  Echinodermen,  p.  7,  pi.  i, 

fig.  15,  1854. 
Forbes.     In  Morris's  Catal.  of  Brit.  Fojs.,  p.  89,  1854. 
Besor.      Synopsis     des    Echinides    foss.,     p.    149,    pi.    sx, 

figs.   1—3,  1856. 
Pictet.      Traite   de   Paleontologie,  t.    iv,  p.    247,  pi.  xcvii, 

fig.  1,   1857. 
Cotleau.     Paleontologie  Francaise,  Terrain  cretace,  tom,  vii, 

p.  144,  pi.  1034,  1864. 


LiatjHosis. — Test  circular,  depressed,  upper  surface  conve.\,  sides  inflated,  base 
narrow,  concave;  ambulacra  wide, prominent,  fle.xed,  two  complete  rows  of  large  marginal, 
and  two  incomplete  rows  of  small  central  granules.  Inter- ambulacra  tliree  times  the 
width  of  ambulacra,  two  rows  of  tubercles,  six  in  each,  large  above  the  ambitus,  small 
below ;  miliary  zone  wide,  sparsely  granulated ;  apical  disc  smooth,  large,  margin 
undidated,  sutures  marked  with  punctuations  ;  vent  circular,  periprocte  thin  and 
prominent. 

Dimensions. — Altitude,  four  tenths  of  an  inchj  latitude,  seven  tenths  of  an  inch. 


FROM  THE  UPPER  GREENSAND.  171 

Description. — This  beautiful  Urchin,  so  long  known  to  collectors  of  Upper  Greensand 
fossils,  has  a  subglobose  body,  depressed  above,  flat  below,  and  with  inflated  sides ;  the 
ambulacral  areas,  gently  flexed,  stand  out  more  prominently  than  the  inter-ambulacrals ; 
they  have  two  complete  rows  of  larger  granules  on  the  margins  of  the  area,  and  two 
incomplete  rows  of  smaller  ones  within  (fig.  1  c,  d,  and  fig.  2  h)  ;  the  poriferous  zones  are 
very  narrow,  depressed,  and  much  flexed,  and  the  pores,  which  are  unigeminal  throughout 
(fig.  1  f/),  are  arranged  in  oblicioe  pairs,  separated  by  a  prominent  tubercle  on  the  septum 
(fig.  2  h).  The  inter-ambulacral  spaces  are  three  times  as  wide  as  the  ambulacral,  with 
two  rows  of  tubercles,  having  six  in  each  row,  those  above  the  ambitus  are  large  and  well 
developed  (fig.  1  b,  d),  those  below  are  small,  and  decrease  nuich  in  size  as  they 
approach  the  peristome  (fig.  2  a) ;  the  base  acquires  an  ornamented  appearance  from 
the  number  of  small  primary  tubercles  that  adorn  it  (fig.  2  a).  Each  tubercle  is  sur- 
rounded  by  a  wide  areola,  around  which  a  more  or  less  complete  circle  of  large  granules 
is  regularly  arranged  (fig.  1  d),  and  most  of  these  granules  are  mammillated;  the  miliary 
zone  is  wide  below,  and  increases  in  diameter  above ;  throughout  it  is  covered  with  small 
granules  nearly  of  the  same  size  (fig.  1  c  andf/).  At  the  base  of  the  area  the  primary 
tubercles  and  granules  are  disposed  as  in  fig.  3,  where  a  portion  of  the  area  is  magnified 
six  times  ;  and  a  profile  of  one  tubercle  is  given  in  fig.  4,  magnified  four  times. 

The  base  is  flat,  and  concave  towards  the  centre,  the  mouth-opening,  one  third  the 
diameter  of  the  test,  is  sunk  in  a  depression ;  the  peristome  is  deeply  incised,  and  divided 
into  ten  nearly  equal-sized  lobes  (fig.  2  a,  fig.  4  (5). 

The  apical  disc  forms  a  very  regular  structure  in  this  species ;  the  antero-lateral  and 
postero-lateral  ovarial  plates  have  a  rhomboidal  figure,  and  the  single  or  suranal  plate  is 
smaller  in  consequence  of  the  position  of  the  vent ;  the  oviductal  holes  are  perforated  near 
the  centre  of  the  plates ;  and  the  madreporiform  body  is  seen  as  a  slight  laceration  on  the 
surface  of  the  right  antero-lateral  in  some  well-preserved  specimens  only.  The  ocular 
plates  are  much  smaller,  and  transversely  or  subtriangularly  oblong,  their  inner  sides 
forming  the  prominent  portions  of  the  triangle,  and  their  frontal  margins  the  bases.  The 
suranal  plate  occupies  the  centre  of  the  disc  before  the  vent ;  it  is  nearly  as  large,  and  of  the 
same  form  as  one  of  the  ovarials,  and  the  lines  of  the  sutures  present  many  punctuations. 
At  the  angles  of  junction  of  every  three  plates  is  a  deep  punctuation,  and  another  in  the 
line  of  union  between  every  two  plates.  Thus  there  are  nine  punctuations  around  the 
borders  of  the  three  anterior  ovarials,  six  around  each  of  the  posterior  ovarials,  and  three 
around  the  oculars  (fig.  1  e,  b).  The  pits  at  the  junction  of  three  plates  are  triangular, 
and  those  at  the  junction  of  two  circular ;  they  are  never  prolonged  as  linear  notches  into 
the  substance  of  the  plates,  as  in  Pdlastcs  dathralus  and  P.  Bunhuryi.  The  vent  is 
subcircular,  excentral,  and  inclines  to  the  right  side ;  the  periprocte  is  elevated  and  pro- 
minent, and  bordered  by  a  rim  formed  of  the  elevated  margins  of  the  suranal,  right 
postero-lateral,  and  single  ovarial  plates.  There  is  considerable  variation  in  the  size  of 
the  punctuations  and  the  width  of  the  lines  of  suture ;  but  these  variations  have  all  their 


172  SALENIA 

connecting  links,  and  fall  within  the  general  description  given  of  the  punctuations  on  the 
sutural  lines  of  the  discal  elements. 

Affinities  and  Differences. — Salenia  petalifera  forms  an  excellent  type  of  the  true 
Salenia,  and  a  leading  fossil  of  the  beds  in  which  it  is  contained.  I  cannot  appreciate 
the  differences  which  some  naturalists  point  out  between  this  species  and  S.  scutigera, 
Miinster ;  and  as  I  have  never  seen  a  true  type  of  that  species,  I  must  reserve  my 
opinion  until  I  can  make  a  comparison  between  them.  After  many  careful  examinations 
of  Herr  Hohe's  figure  in  the  '  Petrefacta,'  and  knowing  the  extreme  accuracy  and  truth- 
fulness of  that  excellent  artist's  admirable  drawing,  I  am  inclined  to  think  that  Cidarites 
scutiger,  Miinster,  is  only  a  smaller  form  of  S.  ])etalifera,  Desm. ;  but  as  most  competent 
authorities  have  ruled  it  otherwise,  I  have  not  put  8.  scutigera  in  my  list  of  synonyms. 

8.  petalifera  resembles  8.  Austeni,  Forb. ;  the  latter,  however,  has  a  more  elevated  test 
with  a  smaller  apical  disc,  and  more  prominent  periprocte.  It  very  much  resembles 
8alenia  giblia,  from  the  same  stratum  of  Upper  Greensand,  which  may  Ije  only  a  variety 
of  8.  petalifera :  a  closer  comparison  between  these  two  allied  forms  will  be  found  in  the 
description  of  8.  gihha. 

Locality  and  8tratigraphical  Position. — 8ulenia  petalifera  was  at  one  time  an  abundant 
fossil  in  the  Upper  Greensand  of  Longleat,  Wilts  ;  but  has  now  become  more  rare.  It  is 
collected  from  the  Grey  Chalk  near  Folkestone,  where  some  very  fine  examples  are  some- 
times obtained.  I  have  long  noticed  that  nearly  all  the  Upper  Greensand  Echinidse 
are  found  in  the  Grey  Chalk,  and  that  the  specimens  from  the  latter  stratum  are  in  general 
larger  and  more  fully  developed,  as  if  they  had  been  better  nourished,  than  those  collected 
from  the  arenaceous  beds  of  the  Upper  Greensand  of  Wilts  and  other  localities. 

History. — This  Urchin  has  long  been  considered  to  be  a  leading  English  fossil  of  the 
Upper  Greensand ;  and  Parkinson,  1811,  Smith,  1816,  Konig,  1820,  have  all  given  good 
figures  of  this  Echinite. 

Foreign  Distribution. — In  the  Craie  Chloritee  de  Cap-la-Heve,  and  other  parts  of 
France,  in  Bavaria  and  Minorca,  and  in  the  "  Hils-Congloraerat "  of  North  Germany. 


Salenia  Loriolii,  Wright,  nov.  sp.     PI.  XXXV,  fig.  1  a — d. 

Diagnosis. — Test  small,  circular,  depressed ;  upper  and  under  surfaces  flattened ; 
ambulacra  straight,  narrow,  two  rows  of  marginal  homogeneous  granules ;  inter- 
ambulacra  wide,  four  or  five  tubercles  in  each  row ;  decreasing  gradually  in  size  from  above 
downwards ;  apical  disc  large,  border  slightly  undulated,  surface  flat,  smooth  ;  ovarial  plates 
without  sutural  lines  or  punctuations  in  the  middle  of  the  disc,  and  with  ten  round  aper- 
tures near  the  outer  border ;  mouth-opening  large,  peristome  deeply  incised,  lobes  unequal. 

Dimensions. — Altitude,  two  lines  ;  latitude,  four  lines. 

Description. — This  small  Urchin  exhibits  a  form  of  apical  disc  very  unusual  among  the 


FROM  THE  UPPER  GREENS  AND.  173 

Salenid^.  The  test  is  depressed  on  the  upper  and  under  surfaces,  and  the  sides  are 
inflated  between.  The  poriferous  zones  are  narrow,  and  the  pores  unigeminal  throughout. 
The  aiubulacral  areas  are  straight  and  narrow,  with  twelve  pairs  of  marginal,  close-set, 
homogeneous  granules,  and  a  few  granulations  between  them  at  the  widest  part  thereof 
(fig.  1  d).  The  inter-anibulacral  areas  are  wide,  and  filled  with  two  rows  of  large  tubercles, 
four  in  each  row ;  those  in  the  upper  part  of  the  area  are  the  largest,  and  they  gradually 
diminish  in  size  from  above  downwards  ;  the  bosses  of  the  tubercles  are  very  prominent,  and 
their  summits  sharply  crenulated ;  the  mammillon  likewise  is  large  ^g.  1  d).  Two  rows  of 
large  granules  occupy  the  miliary  zone,  and  describe  a  zig-zag  ornamentation  on  each  side 
of  the  mesial  suture,  and  two  granules  occupy  the  angles  of  each  of  the  plates  at  their  zonal 
side,  so  that  the  test  of  this  small  species  has  a  highly  ornamented  appearance  (fig.  1  c,  d). 

The  apical  disc  is  large,  solid,  and  remarkable  for  the  absence  from  its  ovarial  plates  of 
sutural  lines  or  punctuations ;  its  border  is  thickened,  and  recurved,  and  near  this  marginal 
bourrelet  are  ten  wide  equidistant  punctures  (fig.  1  a) ;  the  vent  is  round,  the  periprocte 
annulated,  not  much  elevated,  and  slightly  excentral  (fig.  1  a,c). 

The  mouth-opening  is  very  large,  one  half  the  diameter  of  the  test ;  the  peristome  is 
deeply  incised,  and  the  oral  lobes  are  slightly  unequal  (fig.  1  b). 

Jffinities  and  Bifferences. — Salcnia  Loriolii  resembles  Salenia  minima  in  the  closely 
united  sutures  of  its  apical  disc,  but  differs  from  it  in  the  larger  development  of  its  tubercles 
and  wideness  of  its  mouth-opening.  It  differs  from  Salenia  Besori,  associated  with  it  in 
the  same  "  terrain"  in  which  it  is  found,  in  possessing  larger  tubercles,  a  smooth  disc  without 
punctuations,  and  a  much  larger  mouth-opening.  A  comparison  of  the  capital  figures  of 
these  two  Salenice  on  the  same  plate  places  their  affinities  and  differences  better  before  the 
student  than  any  verbal  description. 

Locality  and  Stratigrapldcal  Position. — This  rare  specimen  belongs  to  the  British 
Museum,  and  was  collected  from  the  Upper  Greensand  near  Warminster. 

I  have  dedicated  this  Urchin  to  my  friend  Monsieur  P.  de  Loriol,  of  Geneva,  one  of 
the  learned  authors  of  the  '  Echinologie  Helvctique,'  and  of  several  other  important  works 
on  the  Geology  and  Palaeontology  of  Switzerland. 


Salenia  Desori,  Wright,  nov.  sp.     PI.  XXXV  fig.  2  a—f. 

Biagnosis. — Test  small,  circular,  depressed,  upper  surface  convex ;  ambulacra  straight, 
narrow,  with  two  rows  of  mammillated  granules ;  inter-ambulacra  wide,  four  or  five 
moderate-sized  tubercles  in  each  row ;  pores  unigeminal  throughout ;  apical  disc  promi- 
nent, with  large  punctuations  along  the  sutural  lines  ;  mouth-opening  moderate ;  peristome 
deeply  incised ;  lobes  nearly  equal. 

Bimensions. — Latitude,  four  and  a  half  lines ;  altitude,  two  and  a  half  lines. 

Bescription. — This  pretty  little  Salenia  was  collected  with  S.  Loriolii  in  the  Upper 


174  SALENIA 

Greensaiid  of  "Wiltshire.  The  test  is  small  and  circular ;  the  upper  surface  convex,  and 
the  base  flat;  the  sides  are  inflated,  and  the  disc  conspicuous  and  prominent. 

The  ambulacral  areas  are  straight,  with  two  rows  of  prominent  homogeneous  granules 
on  their  margins,  and  oblique  rows  of  small  granulations,  thi'ee  in  each,  between  every 
pair  of  marginal  granules  (fig.  2/,  2  c).  The  pores  are  unigeminal,  the  pairs  slightly 
oblique,  and  the  zones  narrow  and  straight. 

The  inter-ambulacral  areas  are  wide,  and  the  two  rows  of  primary  tubercles  are  placed 
close  to  the  pores,  so  that  the  miliary  zone  is  wide  and  filled  with  granules  of  different 
sizes  (fig.  2  c) ;  the  tubercles  are  of  moderate  dimensions,  and  gradually  decrease  from 
above  downwards.  Four  of  the  five  sides  of  each  plate  are  encircled  with  a  row  of 
mammillated  granules  (fig.  2/). 

The  apical  disc  is  large,  solid,  and  prominent,  the  border  gently  undulated,  and  the 
sutural  lines  soldered  up ;  in  lieu  thereof,  there  are  three  large  punctuations  between  tlie 
junctions  of  the  three  anterior  ovarial  and  sur-anal  plates,  and  between  all  the  ocular 
plates  and  ovarials ;  the  oviductal  holes  are  large ;  the  vent  is  round ;  the  periprocte 
thickened,  ])rominent,  and  slightly  excentral  (fig.  2  a,  2  d). 

The  mouth-opening  is  nearly  half  the  diameter  of  the  test ;  the  peristome  is  deeply 
incised,  and  the  lobes  are  nearly  equal  (fig.  2  b). 

Affinities  and  Differences. — Salenia  Besori  resembles  S.  gibba.  It  has,  however,  fewer 
granules  in  the  ambidacra,  the  inter-ambulacra  are  more  regularly  developed,  the  apical 
disc  is  without  sutures,  and  the  mouth-opening  is  larger  in  proportion  to  the  diameter 
of  the  test. 

Locality  and  Stratiyraphieal  Position. — This  rare  Urchin  was  collected  from  the  Upper 
Greensand  near  Warminster.  I  have  dedicated  it  to  my  friend  Professor  E.  Desor,  of 
Neuchatel,  one  of  the  learned  authors  of  the  '  Catalogue  raisonne  des  fichinides '  and 
'  Echinologie  Helvetique,'  and  author  of  the  '  Synopsis  des  Echinides  fossiles '  and  many 
other  valuable  works  on  natural  science. 


SalEiNIA  gibba,  Agassis.     PI.  XXXIV,  fig.  4  a,  b,  c,  d,  e. 

Salenia  gibba,  Jgassiz.     Monogr.  des  Snleniea,  p.  13,  pi.  ii,  figs.  9 — Ifi,  1838. 

—  —       Ayassiz  ei  Desor.     Catalog,  rais.  des  Echinides,  Ann.  Sc.  Nat.,  3e  serie, 

t.  vi,  p.  341,  1846. 

—  —       Bronn.     Index  Palaiontologicus,  p.  1107,  184". 

—  —       d'Orhigny.     Prod,  de  Pal.  strat.,  t.  ii,  p.  180,  1850. 

—  —       Morris.     Catalogue  of  British  Fossils,  2nd  ed.,  p.  89,  1856. 

—  —       Piclet.     Traite  de  Paleontologie,  t.  iv,  p.  248,  1857. 

—  —       Cotteau.     Paleontologie  Frau9aise,  Terrain  cretace,  torn,  vii,  p.    151, 

pi.  1035,  figs.  13—20,  1865. 

Z>^ffy??oiM-.— Test  small,  circular,  Upper  surface  inflated,  gibbous,  under  surface  flat, 


FROM  THE  UPPER  GREEN  SAND.  175 

sides  rounded  ;  ambulacra  narrow,  flexed,  two  rows  of  marginal,  closely  set,  mammillated 
granules,  with  intermediate  graiudation  ;  poriferous  zones  Hexed ;  pores  small,  oblique, 
unigeminal;  inter-ambulacra  wide,  tubercles  large  and  prominent  above,  four  or  five  in  a 
row.  Apical  disc  thick,  gibbous,  subconical ;  sutural  impressions  deep,  punctuations  large, 
vent  circular,  periprocte  elevated. 

Dimensions. — Specimen  a.  Altitude,  two  lines  ;  latitude,  four  lines. 
„         b.  Altitude,  five  lines ;  latitude,  six  lines. 

Description. — The  type  specimens  of  this  species  figured  by  Professor  Agassiz  and 
M.  Cotteaii,  from  the  Cenomanian  of  France,  have  a  more  elevated  gibbous  test 
than  any  of  the  specimens  referred  to  Salcnia  (jihha  that  I  have  seen  from  the  Upper 
Greensand  of  England.  The  shell  is  small  and  circular,  the  upper  surface  elevated, 
the  under  surface  flat,  and  the  sides  inflated.  The  ambulacral  areas  are  narrow,  and 
flexed  in  their  upper  third ;  they  have  two  rows  of  mammillated  marginal  granules  set  close 
together,  from  eighteen  to  twenty  in  a  series  (fig.  4  e),  and  the  surface  of  the  space 
between  the  granules  is  covered  with  a  microscopic  granulation.  The  poriferous  zones 
are  depressed,  and  follow  the  flexures  of  the  areas ;  the  pores  are  small,  round,  and 
unigeminal,  and  disposed  in  oblique  pairs,  the  two  pores  forming  a  pair  being  separated 
by  a  septal  granule  (fig.  4  e). 

The  inter-ambvdacral  areas  are  wide,  and  the  tubercles,  of  which  there  are  four  or 
five  in  a  series,  are  large,  prominent,  and  distant  at  the  upper  surface,  and  small, 
granuliform,  and  closely  set  together  below  (fig.  4  b  and  e)\  the  miliary  zone  is  narrow  and 
sinuous,  and  provided  with  unequal  granules ;  some  of  these  are  large  and  mammillated, 
and  disposed  around  the  primary  tubercles  in  incomplete  circles;  others  are  smaller,  and 
fill  the  lower  portion  of  the  zone  with  a  sparse  granulation. 

The  apical  disc  is  thick,  irregularly  round  and  prominent  (fig.  4  c,  d),  and  the  plates  are 
unequal.  The  sutures  are  open  and  incised,  and  the  punctures  deep ;  in  some  specimens 
figured  by  M.  Cotteau  the  disc  is  thick,  gibbous,  and  subconical,  and  the  impressions  are 
wide  and  deep ;  the  surface  of  the  ovarial  plates  has  small  attenuated  elevations,  which 
converge  at  the  centre  of  the  plates.  The  ocular  plates  are  sub-triangular,  and  a[)pear  to 
be  perforated  in  the  middle ;  the  sur-anal  plate  is  large  and  thick,  and  the  oviductal  lobes 
pierce  the  centre  of  the  plates  (fig.  \d).  The  vent  is  sub-circular,  and  the  periprocte 
prominent,  with  an  aniudar  projecting  border. 

The  mouth-opening  is  small,  rather  more  than  one  third  the  diameter  of  the  test 
(fig.  4  h).     The  peristome  is  slightly  incised,  and  the  oral  lobes  are  nearly  equal. 

JJpnities  and  Differences. — In  his  '  Synopsis  des  Echinides  fossiles,'  my  friend 
Professor  Desor  considers  S.(/ibba  as  simply  a  variety  of  8.  scuti(jera ;  it  appears,  however, 
to  have  a  more  infiated  gibbous  form,  with  more  flexuous  ambulacra,  a  thicker  apical 
disc,  more  unequal  in  outline,  and  marked  with  larger  and  deeper  perforations ;  and  the 
mouth-opening  is  hkewise  proportionally  smaller. 

The  structure  of  the  apical  disc  allies  8.  gibba  to  8.  Bourgeoisi ;   the  test  of  the 


176  SALENIA 

latter  is  much  less  inflated,  the  apical  disc  thinner  and  more  depressed,  the  ambulacra 
are  straighter,  and  the  mouth-opening  wider. 

Locality  and  Stratiyraphical  Position. — The  specimen  I  have  figured  belongs  to  the 
British  Museum,  and  was  collected  from  the  Upper  Greensand  near  Longleat,  Wilts,  where 
it  is  extremely  rare.  This  species  appears  to  be  equally  scarce  in  France ;  as  it  was 
obtained  from  the  Cenomanian  =  Upper  Greensand,  in  the  "  He  d'Aix"  (Charente-Infe- 
rieure).  From  this  locality  the  type  specimens  in  the  Musee  de  Paris  and  others  in 
private  collections  were  collected. 


B. — Species  from  the  Grey  Chalk. 

Salenia  Austeni,  Torhes.     PI.  XXXVII,  figs.  1,  2. 

Salenia  Austeni,  Forbes,  MS.     Woodward,  Mem.  Geol.  Siirv.,  Decade  V,  App.,  1856. 
—  —         Forbes.     In  Morris's  Catalogue  of  British  Fossils,  p.  89,  185-1. 

Diagnosis. — Test  tumid,  more  or  less  elevated;  ambulacra  prominent,  slightly 
flexed,  two  complete  rows  of  remote  marginal  granules  and  two  incomplete  rows  of  smaller 
granules  within  ;  inter-ambulacra  with  two  rows  of  tubercles,  five  in  each,  decreasing  in 
size  from  above  the  ambitus  to  the  peristome.  Miliary  zone  wide,  sparsely  covered  with 
granules.  Apical  disc  small,  thick,  prominent ;  sutures  marked  by  regular  punctuations ; 
vent  elevated,  periprocte  projecting,  having  a  sharply  crenulated  border. 

Dimensions. — Altitude,  five  tenths  of  an  inch ;  latitude,  seven  tenths  of  an  inch. 

Description.— 1\\\s,  beautiful  Salenia  has  in  general  a  tumid  body,  with  a  narrow  base, 
inflated  at  the  sides,  and  convex  on  the  upper  surface,  the  vent  being  very  excentric,  elevated, 
and  prominent;  in  some  examples,  however,  the  upper  surface  is  more  or  less  depressed, 
and  approaches  the  form  of  S.  petalifera. 

The  ambulacral  areas  are  narrow,  nearly  straight,  and  very  prominent ;  they  have  two 
complete  rows  of  remote  marginal  granules,  twenty-four  in  each  (fig.  1  c/),  and  two 
incomplete  rows  of  smaller  central  granules,  which  occupy  two  thirds  of  the  area  (fig.  1/). 
The  poriferous  zones  are  narrow  and  slightly  flexed ;  the  pores  are  very  small,  oblique, 
and  unigeminal,  ten  pairs  occupying  the  height  of  a  single  plate  (fig.  1/and  ^7). 

The  inter-ambulacral  areas  are  wide,  and  regularly  developed  (fig.  1  a),  with  two  rows  of 
primary  tubercles,  gradually  diminishing  in  size  from  the  upper  to  the  lower  part  of  the 
area,  those  near  the  disc  being  large,  and  those  near  the  peristome  small.  Fig.  1  e  shows 
an  entire  area  magnified  four  diameters;  the  tubercles  are  seated  near  the  poriferous 
zones  ;  each  is  surrounded  by  a  wide,  areolar  space,  and  around  the  margin  thereof  three 
parts  of  a  circle  of  six  to  eight  large  round  granules  are  placed  (fig.  1  d,  e,  g). 

The  miliary  zone  is  wide  throughout,  and  sparsely  covered  with  small  granules,  especially 
near  the  discal  region  (fig.  1  d,  e).     The  base  is  concave  (fig.  1  b),  and  highly  ornamented 


FROM  THE  GREY  CHALK.  177 

by  the  numerous  small  close-set  tubercles  of  the  inter-ambulacra,  the  large  granules  of 
the  ambulacra,  and  the  width  of  the  miliary  zones.  The  mouth-opening  is  large,  more  than 
one  third  the  diameter  of  the  test ;  the  peristome  is  deeply  incised,  and  forms  ten  nearly 
equal-sized  lobes  (fig.  1  b). 

The  apical  disc  is  small  and  thick,  and  rises  above  the  test  (fig.  1  c  and  d).  The 
two  antero-lateral  and  the  left  postero-lateral  plates  have  a  rhomboidal  figure,  and 
are  nearly  the  same  size.  The  right  postero-lateral,  the  single  plate,  and  the  suranal  are 
small  in  consequence  of  the  encroachment  of  the  vent ;  the  posterior  border  of  the 
suranal  is  thickened  and  elevated  (fig.  1  c,  d,  i),  and  rises  to  form  the  anterior  wall 
of  the  periprocte ;  the  sutures  between  the  three  anterior  ovarial  plates  are  each 
marked  by  six  deep  punctuations,  which  define  their  line  of  junction ;  and  the  sutures, 
uniting  the  ocular  with  the  ovarial  plates,  have  each  three  deep  punctuations  (fig.  1  c  and 
fig.  1  i).  The  test  I  have  figured  has  not  the  perforations  in  the  ovarial  sutures  as  distinctly 
marked  as  the  test  which  now  lies  before  me  for  description,  so  that  this  character  varies 
in  different  specimens.  The  vent  is  round  and  elevated,  and  placed  near  the  posterior 
part  of  the  disc  (fig.  1  c).  The  periprocte  projects  upward  and  backward  (fig.  1  a  and  (/), 
and  forms  a  crenulated  rim  around  the  aperture  (fig.  1  a,  fig.  1  d,  and  fig.  1  i). 

Affinities  and  Differences. — In  a  large  majority  of  specimens  the  general  form  of  the 
body  in  8.  Austeni  differs  from  S.  j)etaUfera  in  being  more  globose  and  elevated.  The 
apical  disc  is  smaller  in  diameter,  and  thicker  in  substance.  The  vent  is  likewise  more 
elevated,  the  periprocte  more  produced,  and  its  margin  sharply  crenulated.  In  the 
structure  of  the  areas,  such  as  the  character  of  the  granules  in  the  ambulacra,  and  the 
tubercles  in  the  inter-ambulacra,  there  is  a  close  resemblance  between  these  portions  of 
the  test  in  both  species. 

Locality  and  Stratigraphical  Position. — S.  Austeni  is  the  most  abundant  species  in 
the  Lower  or  Grey  Chalk,  near  Folkestone ;  from  this  locahty  and  stratum  it  has  been 
collected  by  my  kind  friend,  the  Rev.  T.  Wiltshire,  F.G.S.,  to  whom  I  am  indebted  for 
several  fine  specimens  given  to  help  me  in  my  work. 

History. — Named  by  the  late  Professor  Edward  Forbes,  but  not  described  by  him. 
A  brief  diagnosis  of  the  species  was  given  by  my  late  friend  Dr.  Woodward,  in  the 
Appendix  to  the  Fifth  Decade  of  the  '  Memoirs  of  the  Geological  Survey.'  It  is  now  figured 
and  described  in  detail  for  the  first  time. 


Salenia   Clarkii,  Forbes.     PL  XXXVIII,  fig.   1 ;    PI.  XXXIX,   fig.  1 ;    PI.  XLII, 

figs.  1,  2,  5. 

Salenia  Clarkii,  Forbes.     In  Morris's  Catalogue  of  British  Fossils,  p.  89,  1856. 
—  —         Woodward.     Mem.  Geol.  Surv.,  Decade  V,  App.,  p.  5,  1856. 

Diagnosis. — Test    globose,   elevated,    flattened    on  the   upper   and    under  surfaces; 

23 


178  SALENIA 

ambulacra  narrow,  two  complete  rows  of  marginal  granules,  and  a  few  small  central ;  inter- 
ambulacra  wide,  two  rows  of  primary  tubercles  large  in  the  upper  part,  small  below ; 
apical  disc  half  the  diameter  of  the  test,  plates  roughened  with  raised  points  ;  each  ovarial 
plate  with  five  fun-ows  leading  to  the  large  sutural  pores.  Spines  slender,  cylindrical, 
finely  striated  and  granulated,  the  longest  exceeding  If  inches  in  length,  and  less  than  one 
line  in  diameter  ;  frequently  forked  at  their  extremities,  and  sometimes  bent  and  otherwise 
distorted. 

Dimensions. — Height,  nine  twentieths  of  an  inch  ;  latitude,  thirteen  twentieths  of  an 
inch. 

Description, — This  very  distinct  form  of  Salenia  has  an  elevated  body,  depressed  and 
flattened  on  the  upper  and  under  surfaces ;  the  ambulacral  areas  are  narrow  and  straight 
(fig.  1  d,)  with  two  complete  rows  of  marginal  granules,  about  twenty  in  each ;  within  these 
are  two  incomplete  rows  of  small  irregular  granules,  having  a  microscopic  granulation 
scattered  around  their  base.  Fig.  1  ^  shows  an  ambulacral  area  magnified  four  times, 
and  exhibits  the  increase  in  volume  of  the  marginal  granules  near  the  base  of  the  area.  The 
poriferous  zones  are  narrow  ;  the  pores  form  oblique  pairs  with  a  thick  septum  between,  and 
having  a  small  granular  elevation  on  the  sm'face :  fig.  1  h  shows  this  structure  magnified 
six  diameters,  as  well  as  the  minute  granulation  on  the  surface  of  the  plates,  and  the 
comparative  sizes  of  the  marginal  and  central  granules  in  the  area.  The  number  of  pores 
opposite  each  large  plate  is  eiglit  or  nine  pairs. 

The  inter-ambulacral  areas  are  wide  above  and  narrow  below ;  there  are  six  primary 
tubercles  in  each  of  the  two  rows,  and  of  these  the  four  above  the  ambitus  are  much  the 
largest ;  those  on  the  under  side  are  much  smaller  and  set  closely  together  ;  all  the  tubercles 
have  wide  areolar  spaces,  which  are  encircled  for  three  parts  of  their  circumference  with  a 
series  of  large,  remote,  well-developed  granules.  Fig.  1/  shows  an  entire  inter-ambulacral 
space  magnified  four  diameters,  and  fig.  1  /^  a  single  plate  with  its  primary  tubercle, 
areolar  space,  and  circle  of  marginal  granules,  with  the  poriferous  zones  and  ambulacra, 
magnified  six  diameters.  The  miliary  zone  (fig.  1/)  is  wider  below  the  ambitus,  and  is 
here  filled  with  an  abundant  granulation  (fig.  1  c,  fig.  1/) ;  above  the  ambitus,  the  large 
size  of  the  tubercles  diminishes  the  width  of  the  zone,  and  the  tubercles  here  are  fewer 
and  larger  (fig.  1/,  fig.  1  b,  and  fig.  1  d). 

The  apical  disc  is  one  half  the  diameter  of  the  test,  and  the  surface  of  the  plates  is 
roughened  with  many  raised  points  (fig.  1  b) ;  each  ovarial  plate  has  five  furrows  leading 
to  the  sutural  pores,  which  have  an  arrangement  similar  to  the  punctuations  on  the  disc 
in  S.petalifera ;  a  semicircle  of  seven  punctures  indicates  the  sutures  by  which  the  sur-anal 
is  united  to  the  three  anterior  ovarials ;  one  large  and  two  smaller  punctures  mark  the 
line  of  union  between  the  ocular  and  ovarial  plates.  In  fig.  1  e  the  apical  disc  is  magnified 
four  diameters ;  and  the  sutural  punctuations  are  very  correctly  delineated  in  this  drawing. 

The  spines  of  Salenia  ClarJcii  are  very  well  preserved  with  the  test  in  the  unique 
specimen  belonging  to  the  Museum  of  the  Royal  School  of  Mines,  and  which  I  have  figured 


FROM  THE  LOWER  WHITE  CHALK.  179 

in  PI.  XXVHI,  fig.  2  a.  The  spines  are  slender,  cylindrical,  finely  striated,  and  granulated  ; 
the  longest  exceed  If  inches  in  length,  and  are  less  than  the  twelfth  of  an  inch  in  diameter  j 
some  of  the  spines  are  bent,  as  in  figures  3  and  4,  some  are  spatulate  (fig.  2  h),  and  others 
are  forked  (fig.  2  c)  at  their  extremities.  The  base  of  the  spine  around  the  milled  ring 
has  fine  longitudinal  lines  extending  a  short  distance  up  the  stem,  which  is  likewise  covered 
by  finer  microscopic  lines  (fig.  2  d,  and  figs.  3  and  4)  extending  along  the  stem. 

Affinities  and  Differences. — This  species  very  much  resembles  8.  gihba ;  but,  according 
to  Dr.  Woodward,  it  is  entirely  distinct  from  the  mould  of  Professor  Agassiz's  original 
example  of  that  species. 

Locality  and  Stratigraphical  Position. — Salenia  Clarkii  is  very  rare  in  the  Grey  Chalk 
near  Folkestone  ;  from  this  "  terrain  "  the  specimens  in  the  Royal  School  of  Mines  and  the 
British  Museum  were  obtained. 

Histonj. — First  named  by  the  late  Professor  Edward  Forbes,  in  his  additions  to  the 
Echinodermata  in  the  2nd  edition  of  Professor  Morris's  Catalogue  of  British  Fossils. 
A  diagnosis  of  the  species  was  subsequently  drawn  up  by  Dr.  Woodward,  in  his  Appendix 
to  Decade  V,  Memoirs  of  the  Geological  Survey,  illustrative  of  Organic  Remains.  It  is 
now  figured  in  detail  from  specimens  contained  in  the  Cabinet  of  the  Rev.  T.  Wiltshire, 
F.G.S.,  and  in  both  our  National  Collections, 


B. — Species  from  the  Loioer  White  Chalk. 
Salenia  granulosa,  Forbes.     PI,  XLI,  figs.  2,  3  ;  PL  XLIII,  fig.  1  a — h. 

Salenia  scutigera,     Forbes.     In  Dixon's  Geol.  Foss.  Susse.x,  pi.  ?,AQ,  pi.  xxv,  fig.  24, 
1850. 

—  HELIOPHOKA,  Sorignet.     Oursins  de  I'Eure,  p.  20,  1  S.'iO. 

—  GRANULOSA,     Forbes.     In  Morris's  Catalogue  of  Brit.  Foss.,  p.  89,  1854. 

—  -  Woodward.     Mem.  of  Geol.  Siirv.,  Dec.  V,  1856. 

—  INCRUSTATA,   Cotteau,  in  Desor's  Synops.  des  Ech.  foss.,  p.  152,  1856. 

—  GRANULOSA,     Pictet.     Trait^  de  Paleontologie,  t.  iv,  p.  218,  1857. 

—  —  Cotteau.     Paleontologie    Francaise,  Terrain  Cretace,    torn,    vii, 

p.  167,  pi.  1039,  figs.  6—21,  1860. 

Diagnosis. — Test  small,  circular,  depressed,  upper  surface  convex,  under  surface  flat; 
ambulacra  narrow,  slightly  flexed,  with  two  rows  of  marginal  mammillated  granules  ;  inter- 
ambulacra  wide,  much  covered  by  a  prolongation  of  the  ovarial  plates,  tubercles  small, 
surrounded  by  areolas ;  apical  disc  very  large,  covering  like  an  incrustation  nearly  the 
entire  upper  surface;  the  flat  ovarial  plates  have  flexuous  lines  of  granular  processes 
diverging  from  their  centres,  and  the  convex  oculars  have  similar  hues  extending  over  them 
from  their  inner  side ;  the  sutures  smooth,  and  without  impressions. 


ISO  SALENIA 

Bimensions. — Specimen  a.  Altitude,  four  lines ;  latitude,  five  lines. 

„         b.  Altitude,  four  and  a  half  lines  ;  latitude,  six  and  a  half  lines. 

Description. — This  beautiful  species  was  first  noticed  by  M.  I'Abbe  Sorignet,  in  his 
description  of  '  I'Oursins  de  I'Eure,'  and  referred  by  him  to  Ili/posalenia  heliophora  from 
the  Upper  Chalk  (Danian)  of  Ciply,  which  M.  Desor'  described  as  "  distinguished  by  its 
very  much  ornamented  disc,  each  ovarial  and  ocular  plate  being  the  centre  of  a  system  of 
fine  ridges,  that  radiate  in  all  directions."  This  species  was  not  figured  by  Sorignet;  and 
I  have  not  yet  seen  a  French  specimen  to  compare  with  our  Urchin  from  the  lower 
white  gritty  Chalk  of  Dover,  where  it  has  hitherto  only  been  found. 

The  test  is  small  and  circular,  the  upper  surface  convex,  the  lower  flat,  and  the  sides 
rounded  and  moderately  inflated  (PL  XLI,  fig.  2c;  PI.  XLIII,  fig.  1  d).  The  ambulacral 
areas  are  narrow,  straight,  or  slightly  flexed,  with  two  niai-ginal  rows  of  round  prominent 
granules,  twelve  to  thirteen  in  each  ;  those  near  the  base  are  large  and  raammillated 
(PI.  XLI,  fig.  1  e) ;  those  at  the  ambitus  smaller,  and  on  the  upper  part  very  small  and 
closely  placed  together  ;  the  intermediate  space  being  filled  with  an  unequal  microscopic 
granulation,  which  extends  horizontally  between  the  marginal  granules. 

The  poriferous  zones  are  narrow,  the  pores  unigeminal,  and  set  in  oblique  pairs, 
separated  from  each  other  by  a  small  granuliform  elevation  of  the  septum ;  there  are 
about  eight  pairs  of  holes  opposite  one  of  the  large  inter-ambulacral  plates  (PI.  XLI, 
fig.  2/;  PI.  XLIII,  fig.  1  li,  in  which  I  have  given  accurate  figures  of  this  part  of  the 
test,  magnified  six  times). 

The  inter-ambulacral  areas  are  wide  (PI.  XLI,  fig.  2  d),  and  covered  over  in  their 
upper  third  by  a  lateral  extension  of  the  ovarial  plates  ;  there  are  three  or  four  tubercles  in 
each  row,  which  rise  a  little  above  the  ambitus;  only  one  or  two  of  these  tubercles  in 
each  series  are  well  developed,  surrounded  by  a  circular  areola,  and  having  a  large  boss 
and  prominent  mammillon  (PI.  XLIII,  fig.  1  // ;  PI.  XLI,  fig.  2/).  The  miliary  zone  is 
narrow,  and  its  granules  unequal  in  size  and  structure ;  the  larger  are  distinctly  mammil- 
lated,  and  disposed  in  a  regular  crescentic  form  around  the  areolae ;  where  the  latter  abut 
against  the  poriferous  zones  the  granules  are  absent  (fig.  1  h,  fig.  1  g)  ;  the  other  granules 
are  small  and  irregularly  disposed,  filling  up  the  space  with  a  fine  granulation  (fig.  1  h). 

The  mouth-opening  is  very  small  (PI.  XLI,  fig.  2  (5 ;  PI.  XLIII,  fig.  1  c),  in  excess  of 
one  third  the  diameter  of  the  test ;  the  peristome  is  divided  into  ten  equal  lobes  by  well- 
marked  incisions. 

The  apical  disc  is  very  large  and  pentagonal,  occupying  a  great  part  of  the  upper 
surface  (PI.  XLIII,  fig.  1  b,  d,  e).  It  is  convex  above,  and  so  thin  and  closely  adherent  to 
the  shell  at  the  borders  that  it  appears  to  blend  witli  the  plates  of  the  test ;  the  ovarial 
plates  are  large,  and  of  an  irregular  form  ;  their  surface  is  sculptured  with  small  unequal 
punctuated  lines,  which  appear  to  radiate  outwards  from  the  oviductal  holes  situate  near 

'  'Synopsis  des  ficliinides  fossiles,'  p.  148. 


FROM  THE  LOWER  WHITE  CHALK.  181 

the  centre  of  the  plate ;  the  ridges  on  the  plates  resemble  numbers  of  prominent  gra- 
nulations projecting  outwards,  which  impart  a  granulose  aspect  to  the  surface  of  the  disc, 
and  is  very  well  represented  in  PI.  XLI,  fig.  3,  and  PI.  XLIII,  fig.  1  e ;  a  process 
of  each  plate  extends  into  the  inter-ambulacra,  the  ornamentation  of  which  differs  from 
that  in  the  middle  of  the  plate  ;  the  punctuated  lines  are  widest  and  more  flexed,  and  this 
incrusting  process  appears  to  blend  with  the  granidations  on  the  test ;  the  sur-anal  plate  is 
elevated,  and  forms  the  anterior  border  of  the  periprocte ;  the  ocular  plates  are  heart- 
shaped,  and  more  prominent  than  the  ovarials ;  they  are  likewise  covered  with  punctuated 
flexuous  ridges,  but  the  lines  are  more  tortuous,  and  the  style  of  ornamentation  is  different 
(PI.  XLIII,  fig.  1  e)  from  that  on  the  ovarials. 

The  spines  are  not  preserved  in  any  of  the  Dover  specimens  that  have  passed  through 
my  hands.  M.  Cotteau,  however,  describes  them  as  elongate  or  aciculate,  cylindrical,  or  a 
little  compressed,  provided  with  fine  longitudinal  sub-granular  striae ;  their  greatest  dia- 
meter is  near  the  neck  of  the  spine,  and  they  regularly  diminish  to  the  upper  extremity, 
which  is  pointed.  The  collarette  is  short  or  absent,  the  milled  ring  very  prominent  and 
strongly  striated,  and  the  rim  of  the  articular  cavity  crenulated. 

Affinities  mid  Differences. — Salenia  granulosa,  Forb.,  strongly  resembles  Hyposalenia 
heliophora,  Desor,  from  the  Chalk  of  Maestricht ;  it  is  distinguished  from  it,  however, 
according  to  M.  Cotteau,  by  being  smaller  in  size,  and  having  its  upper  surface  more 
conical,  its  ambulacra  furnished  below  the  ambitus  with  smaller  granules,  and  in  possessing 
fewer  primary  tubercles  in  the  inter-ambulacra ;  the  apical  disc  is  thinner  and  distinctly 
circumscribed,  the  flexuous  ridges  on  the  ovarial  and  ocular  plates  are  more  irregular  and 
more  granular,  and  the  periprocte  is  situated  to  the  right  of  the  axis. 

Locality  and  Stratic/rapldcal  Position. — This  fine  species  is  found  in  the  hard  gritty 
whitish  beds  of  the  Lower  Chalk  at  Dover,  where  it  is  associated  with  Cyphosoma  simplex, 
Forb.,  and  numerous  Polyzoa.  All  the  specimens  I  have  examined  were  obtained  from 
this  one  locality,  where  it  is  rather  rare. 

M.  Cotteau  states  that  it  is  a  common  species  in  the  Jltage  Senonien  of  Vernonnct, 
Giverny,  Petit-Andely,  Penterville  (Eure),  and  the  environs  of  Beauvais  (Oise). 

History. — M.  I'Abbe  Sorignet  first  described  in  1850  this  Salenia  in  his  interesting 
memoir  'I'Oursins  de  I'Eure,'  and  identified  it  as  the  Hyposalenia  lieliophora,  Desor.  In 
the  same  year  the  late  Professor  Forbes,  in  Dixon's  '  Geology  of  Sussex,'  gave  a  figure  of 
this  Urchin,  which  he  referred  to  Salenia  scutiyera,  Gray  ;  subsequently,  in  the  second 
edition  of  Morris's  '  Catalogue  of  British  Fossils,'  1854,  Forbes  separated  it  from  that  species 
under  the  MS.  name  S.  granulosa.  In  1856  M.  Cotteau,  in  M.  Desor's  'Synopsis  des 
fichinides  fossiles,'  named  the  specimens  collected  and  identified  as  Hyposalenia  helio- 
phora  by  M.  Sorignet,  Salenia  incrustata,  Cott. ;  he  gave  the  following  diagnosis  of 
this  form  : — "  Small  Urchins,  well  characterized  by  their  very  large  apical  disc,  thin,  and 
little  in  relief,  and  incrusting  in  some  manner  the  whole  of  the  upper  surface  of  the  test. 
The  ovarial  plates  present  a  series  of  small  points  disposed  like  rays  around  many  centres ; 


183  SALENIA 

the  disc  is  so  intimately  soldered  to  the  test  that  it  is  sometimes  difficult  at  first  sight  to 
recoo-nize  its  limits."  A  comparison  of  the  English  with  the  French  specimens  showed 
them  to  be  specifically  identical,  and  thus  M.  Sorignet  was  the  discoverer,  but  Forbes  the 
namer,  of  this  well  defined  species. 


c. — Species  from  the  Upper  White  Chalk. 

Salenia  geometrica,  Agassiz,  1838.     PI.  XLIII,  fig.  2  a — y,  fig.  3  a,  h. 

Salenia  geometrica,    Agassiz.  Mongr.  Ecbinodermes,  pi.  i,figs.  25 — 32,  p.  11,  1838. 
CiDARis  ?  VESicuLOsus,  Por^/ocA-.     Report  on   the  Geology  of  Londonderry,  pi.  xviii, 

fig.  5,  p.  358,  1843. 
Salekia  scctigera  ?      Forbes.     In  Di.xon's  Geology  of  Sussex,  pi.  xxv,  fig.  23,  1850. 

—  PoRixocKii,     Forbes.    In  Morris's  Cat.  of  Brit.  Foss.,  2nd  ed.,  p.  89,  1854. 

—  —  Woodioard.     Mem.  of  the  Geol.   Surv.,   Decade  V,   Append., 

p.  5,  1856. 

—  GEOMETRICA,     Cotteau  et  Triger.     Echiuides  du  Depart,  de  la  Sarthe,  pi.  xlvi, 

figs.  1—7,  1860. 

—  SCUTIGEKA,       Cotteau,  pars.     Pale'ontologie  Fran9aise,  Terrain  Cretace,  torn. 

vii,  p.  154,  pi.  1036,  1864. 

Diagnosis. — Test  sub-globose,  elevated,  convex  above,  contracted  and  concave  beneath ; 
ambulacra  narrow,  slightly  flexuous,  marginal  granules  separated  by  two  rows  of  granulets ; 
inter-ambulacra  wide,  plates  slightly  radiate  ;  two  rows  of  tubercles,  seven  to  eight  in  each, 
the  ambital  large,  the  basal  small ;  miliary  zone  with  large  sparse  granules  and  minute 
granidations ;  apical  disc  moderate,  of  a  regular  geometrical  figure,  flattened,  two  thirds 
the  diameter  of  test;  sutures  punctuated;  plates  nearly  equal  in  size;  mouth-opening 
small,  one  third  the  diameter  of  test. 

Dimensions. — a.  Altitude,    eight   lines ;    latitude,    nine    lines    (Mr.   Searles  Wood's 
specimen). 
b.  Altitude,  eleven  lines  ;  latitude,  one  inch  (Mr.  King's  specimen). 

Description. — The  species  to  which  this  Urchin  has  been  referred  is  considered  by 
Professor  Desor  and  M.  Cotteau  to  be  the  Salenia  scutigera.  Gray ;  as  I  am  doubtful 
about  the  identity  of  Dr.  Gray's  form,  I  have  retained  the  name  given  by  Professor 
Agassiz,  seeing  that  he  has  published  good  figures  and  a  clear  description  of  this  species 
in  his  beautiful  Monograph  on  the  Salenies.  S.  geometrica  is  the  largest  species  of  the 
genus  at  present  known.  The  test  is  elevated  and  sub-globose,  slightly  flattened  at  the 
upper  and  under  surfaces.  The  ambulacral  areas  are  narrow  and  slightly  flexed,  with  two 
marginal  rows  of  close-set  granules,  fourteen  to  sixteen  in  each,  and  separated  by  a 
double  row  of  minute  granulation  extending  down  the  middle  of  the  area  (PI.  XLIII, 
%•  2  c,g,f).     The  poriferous  zones  are  narrow  and  slightly  flexed,  the  pores  unigeminal 


FROM  THE  UPPER  WHITE  CHALK.  183 

and  oblique  (fig.  r2/),  and  the  septa  between  the  pores  support  prominent  granuliform 
elevations  (fig.  2y). 

The  inter-ambulacral  areas  are  very  wide  throughout  (fig.  3  c,  e,  and  fig.  3  a,  b)  ;  they 
are  formed  of  two  series  of  deep  plates,  seven  in  each,  that  support  large  prominent 
tubercles  (fig.  \Le,g,  fig.  2>a).  The  four  ambital  tubercles  are  the  largest;  they  have 
well-defined  areolas,  prominent  bosses,  and  moderate-sized  mammelons.  A  series  of  mam- 
millated  granules  surround  the  areola,  except  where  it  abuts  against  the  zones  (fig.  2 
e  andy).  The  miliary  zone  is  wide,  and  filled  with  numerous  small  granulations  (fig.  3  e) 
in  addition  to  the  larger  granules  that  encircle  the  tubercles. 

The  apical  disc,  two  thu'ds  the  diameter  of  the  test,  has  a  regular  geometrical  figure, 
hence  the  origin  of  the  specific  name  (fig.  2  a,  6) ;  it  is  circular,  slightly  convex,  and  a 
little  elevated  at  the  vent.  The  ovarial  plates  have  an  irregular  hexagonal  shape,  their 
outer  sides  are  elongated  and  contracted,  and  the  rounded  external  border  lies  within  the 
circle  described  by  the  ocular  plates,  which  have  an  irregular  triangular  figure,  the  largest 
side  being  turned  outwards  and  slightly  undulated  (fig.  2  d) ;  the  sutures  are  fine, 
distinct,  and  regularly  interrupted  by  small  punctuated  angular  impressions;  the  oviductal 
holes  open  in  the  middle  of  the  plates,  and  the  orbits  lie  under  the  central  projecting 
process  (fig.  3  d) ;  the  surface  of  all  the  plates  is  quite  smooth.  The  vent  is  slightly 
elevated,  and  the  periprocte  surrounded  by  a  thick  annulus  (fig.  2  d,  d)  ;  this  aperture, 
nearly  circular,  occupies  the  posterior  half  of  the  sur-anal  and  the  anterior  halves  of  the  two 
posterior  ovarial  plates. 

The  mouth-opening  is  one  third  the  diameter  of  the  test  (fig.  3  d)  ;  and  the  peristome 
is  divided  into  ten  unequal  lobes. 

Affinities  and  Differences. — Salenia geometrica  resembles  ^S*.  scutigera ;  by  some  authors 
it  is  considered  to  be  a  large  variety  of  the  latter.  M.  Cotteau,  in  his  beautiful  Monograph 
on  the  '  Echiuides  du  Departement  de  la  Sarthe,'  figured  and  described  this  Urchin  under 
the  name  Salenia  geometrica,  Ag.,  but  in  his  later  and  most  valuable  contribution  to  the 
'  Paleontologie  ErauQaise'  has  united  it  yf'iih.  Salenia  scutigera ;  he  says,  however,^  as  to 
the  Salenia  geometrica,  "  la  question  est  plus  delicate  et  plus  difficile  a  resoudre.  Au 
premier  abord,  cette  espece  se  distingue  certainement  du  Salenia  scutigera  par  plusieurs 
caracteres  importants :  sa  taille  est  beaucoup  plus  considerable,,  car  sa  hauteur  depasse 
souvent  13  millimetres,  et  son  diametre  17  miUimetres ;  sa  face  superieure  est  plus 
elevee  et  plus  sensiblement  deprimee  au  sommet ;  ses  tubercules  inter-ambulacraires  sont 
plus  nombreux,  et  la  zone  railiare  qui  les  separe  plus  large,  plus  droite  et  plus  granu- 
leuse;  ses  ambulacres  sont  plus  longs  et  plus  flexueux,  et  I'appareil  apicial,  relativement 
moins  grand  et  moins  epais,  afFecte  une  forme  plus  pentagonale.  Ces  difierences  se 
reproduisent  chez  un  certain  nombre  d'individus  avec  une  Constance  qui  n'est  pas 
sans  leur  donner  de  la  valeur ;  aussi,  dans  nos  '  Echiuides  de  la  Sarthe,'  n'avons-nous 
pas  hesite  a,  maintenir  la  S.  geometrica  comme  une  espece  parfaitement  distincte. 

^  'Paleontologie  Fran^aise,  Ter.  Cretace,'  tora.  vii,  p.  157. 


184  SALENIA 

"Les  nombrenx  raateriaux  que  nous  avons  sous  les  yeux,  et  que  nous  venons  de  com- 
parer, nous  engagent  aujourd'hui  ii  revenir  sur  cette  opinion.  Associes  aux  types  les 
mieux  caracterises  il  se  rencontre  des  exemplaires  cliez  lesquels  les  differences  que  nous 
venons  d'enuuierer  s'effacent  plus  ou  uioins,  et  qui  tendent  a  se  rapprocher,  par  des 
passages  insensibles,  du  veritable  S.  scutigera.  Les  uns,  tout  en  conservant  leur  grande 
taille,  sont  moins  renfles,  garnis  de  tubercules  moins  abondants,  et  presentent  un  appareil 
apicial  plus  developpe,  plus  epuis  et  arrondi  au  pourtour ;  les  autres,  plus  petits,  ont  un 
appareil  apicial  qui  cesse  peu  a  peu  d'etre  pentagonal,  et  tend,  en  s'agrandissant  a  s'ar- 
rondir  sur  les  bords.  lis  appartiennent  encore  a  la  variete  yeoMe^nca ;  cependant  ils 
ofFrent  une  grande  ressemblance  avec  les  exemplaires  Cenomaniens  ;  quelquefois  meme  il 
est  diiEcile  de  les  en  separer. 

"  Woodward,  d'apres  Forbes,  decrit  sous  le  nom  de  S.  Portlockii  une  espece  d'assez 
grande  taille,  elevee,  sub-globuleuse,  a  ambulacres  etroits  et  sinueux,  a  disque  apicial 
mediocrenient  developpe  ;  ses  caracteres  la  rapprochent  beaucoup  du  8.  scutigera,  var. 
geometrica.     Peut-^tre  devrait-elle  y  etre  reunie." 

Locality  and  Stratigrapliical  Position. — This  fine  large  species  occurs  in  tbe  Upper 
Chalk  of  the  North  of  Ireland,  where  it  was  collected  by  the  officers  of  the  Geological 
Survey,  and  figured  in  Colonel  Portlock's  '  Report  on  the  Geology  of  the  County  of 
Londonderry.'  It  is  found  very  rarely  in  the  upper  beds  of  white  Chalk  at  Norwich  and 
in  Sussex,  and  flint  moulds  are  not  uncommon  in  the  Gravel  of  Norfolk.  The  specimens 
figured  Iselong  to  the  British  Museum.  Mr.  Searles  Wood  possesses  a  good  example,  and 
Mr.  John  King,  of  Norwich,  has  a  large  one  which  measures  eleven  lines  in  height  and 
as  much  in  diameter.  There  is  also  a  fine  specimen  in  the  Hunterian  Collection,  Museum 
of  the  College  of  Surgeons  (Woodward). 


Salenia  magnifica,  Wright,  nov.  sp.     PI.  XLIV,  fig.  1,  a — /. 

Diagnosis. — Test  spheroidal,  much  elevated ;  ambulacra  nearly  straight,  two  marginal 
rows  of  large  mammillated  and  two  internal  rows  of  smaller  granules;  poriferous  zones 
narrow,  pores  very  oblique  and  unigeminal ;  inter-ambidacra  wide,  two  rows  of  tubercles, 
seven  in  each,  the  ambital  and  dorsal  very  large,  the  basal  very  small ;  miliary  zone  wide, 
and  sparsely  covered  with  granulations  ;  apical  disc  large,  plates  smooth,  sutures  punc- 
tuated, vent  large,  oblong ;  periprocte  hexagonal,  elevated,  and  projecting  ;  mouth-opening 
small,  oblong. 

Dimensions. — Altitude,  nine  lines ;  latitude,  ten  and  a  half  lines. 

Descrijition. — This  magnificent  Salenia  from  the  White  Chalk  belongs  to  the  British 
Museum,  and  to  the  illustration  of  its  finely  preserved  details  I  have  devoted  PI.  XLIV. 
The  test  is  spheroidal  and  much  elevated,  its  altitude  exceeding  its  diameter  by  one  and  a  half 
lines  ;  the  ambulacral  areas  are  narrow  and  slightly  flexed,  with  two  marginal  rows  of  large 


THE 


PALJIONTOGRAPHICAL  SOCIETY. 


INSTITUTED  MDCCCXLVII. 


VOLUME    FOE    1873. 


LONDON 

MDCCClX.Xir. 


MONOGRAPH 


BRITISH     FOSSIL 


ECHINODERMATA 


FROM 


THE  CRETACEOUS  FORMATIONS. 


BY 


THOMAS  WRIGHT,  M.D.,  F.R.S.  Edin.,  F.G.S., 

COBBESPOSDING   MEMBEK  OF   THE    KOYAl   SOCIETY   OF  SCIEKCES  OP  LIEGE,   THE   SOCIETY  OF 
NATTIBAi  SCIENCES   OP  NEUPCHATEL;    SENIOR   SUEGEON  TO   THE    CHELTENHAM 
HOSPITAL;    AND   MEDICAL   OPPICER   OF   HEALTH   FOB,   THE    UBBAN 
SANITARY   DISTRICTS   OF    CHELTENHAM,    CHARLTON- 
KINGS,   AND    LECKHAMPTON. 


VOLUME    FIRST. 

PART  SIXTH. 
ON    THE    ECHINOCONID^. 

Pages  185—224 ;  Plates  XLV— LII. 


LONDON: 

PRINTED   FOR   THE   PAL^ONTOGRAPHICAL   SOCIETY. 

1874. 


FEINTED   BY 
J.    E.    ADLAED,  BAETHOLOMEW    CLOSE. 


FROM  THE  UPPER  WHITE  CHALK.  1S5 

■close-set  mammillated  granules,  twenty-six  iu  each  roAV,  larger  at  the  base  than  in  the 
upper  part  of  the  area.  Within  these  are  two  rows  of  much  smaller  granules,  twenty- 
two  in  each,  less  regular  in  their  arrangement  than  the  marginal  rows  (fig.  1  (/).  The 
poriferous  zones  are  extremely  narrow  and  the  pores  disposed  in  very  oblique  pairs 
(fig.  Iff),  eight  lying  within  the  height  of  one  of  the  large  inter-ambulacral  plates  (fig.  1  i) ; 
the  septum  between  each  pair  terminates  in  a  grauuliform  elevation  (fig.  1  i). 

The  inter-ambulacral  areas  are  vi^ell  developed  (fig.  1  a,  d,  /),  with  two  rows  of 
tubercles,  seven  in  each  ;  those  in  the  upper  part  of  the  area  and  at  the  ambitus  are  large, 
and  at  the  base  small ;  fig.  1  /  shows  one  area  magnified  four  diameters ;  the  three  pairs 
of  large  tubercles  i^early  occupy  the  entire  surface  of  their  respective  plates  (fig.  1  i) ;  the 
boss  has  a  wide  base,  surrounded  by  a  well-defined  areola,  and  this  is  encircled  by  a 
series  of  eight  large  mammillated  granules ;  fig.  1  i  shows  one  of  these  large  plates, 
and  fig.  1  i-  gives  a  profile  of  one  tubercle  with  its  surrounding  granules,  both  figures  are 
magnified  six  diameters ;  from  the  ambitus  to  the  peristome  the  tubercles  gradually 
diminish  in  size,  and  the  four  small  basal  nearest  the  mouth  have  a  row  of  mammillated 
granules  separating  them  from  the  poriferous  zones  (fig.  1/  and  fig.  1  //).  The  miliary 
zone  is  wide,  nearly  of  equal  diameter  throughout;  and  in  addition  to  the  large  granules  which 
form  a  series  of  crescents  around  the  areolae  the  interspace  is  covered  with  small  granules 
sparsely  strewed  over  the  surface  of  the  plates  (fig.  1  d,  y,  /).  The  apical  disc  is 
large  and  prominent,  consisting  of  a  series  of  thick  plates  ;  fig.  1  a  shows  its  natural  size 
and  I'elations,  and  fig.  1  i  the  same  magnified  four  diameters.  Three  of  the  ovarial  plates 
have  an  irregular  hexagonal  and  two  a  rhomboidal  figure  (fig.  1  h  and  e) ;  in  all  the 
oviductal  holes  are  in  the  centre  of  the  plates ;  the  sur-anal  plate  is  much  thickened  and 
raised  to  form  the  anterior  wall  of  the  periprocte  (fig.  1  a,  h,  d,  e) ;  the  ocular  plates  are 
triangular,  having  their  base  undulated  and  turned  outwards  :  the  outer  border  of  both 
the  ovarial  and  ocular  plates  are  placed  within  the  circle  having  its  centre  at  the  anterior 
wall  of  the  vent;  the  sutures  are  well  marked  and  punctated  with  small  angular  im- 
pressions ;  the  vent  is  large  and  oblong  (fig.  1  b,  e),  and  the  periprocte  surrounded  by  a 
thick  prominent  annulus,  which  forms  a  conspicuous  character  of  the  test  of  this  fine 
Salenia ;  the  vent  is  excentral  (fig.  T  a,  d),  and  looks  obliquely  backwards  and  to  the 
right  side.  The  base  is  narrow,  and  highly  ornamented;  the  small  primary  inter- 
ambulacral  tubercles  are  closely  set  together,  and  the  large  mammillated  ambulacral 
granules  are  very  conspicuous,  and  form  a  prominent  band  between  the  tubercles  (fig. 
1  c,  h) ;  the  miliary  zone  is  wide,  and  filled  with  small  close-set  granules  (fig.  \f,  c). 
The  mouth-opening  is  oblong  (fig.  1  e,  /)  about  one  third  the  diameter  of  the  test. 
The  peristome  is  decagonal,  dividing  the  opening  into  ten  unequal  lobes ;  each  of  the 
ambulacral  lobes,  which  are  the  largest,  have  a  double  crescentic  outHne,  fig.  1  h,  I -. 
this  is  the  only  species  of  the  genus  Salenia  which  possesses  an  oblong  mouth-opening, 
and  this  forms,  therefore,  one  of  the  specific  characters  by  which  it  is  distinguished  from 
its  congeners. 

24 


ISG  COTTALDIA. 

Affinities  and  Differences. — This  magnificent  Salenia  in  point  of  size  resembles  S. 
fieometrica,  var.  Portlockii,  ft-om  the  White  Chalk.  The  test,  however,  is  more  elevated, 
the  apical  disc  thicker  and  more  prominent,  and  the  inter-ambulacral  areas  resemble  each 
other  in  the  number  and  development  of  the  tubercles  in  each  rovi' ;  the  oblong  vent  and 
oblong  mouth-opening  are,  however,  special  to  S.  magnifica. 

Locality  and  StratigrapJiical  Position. — This  Urchin  was  collected  from  the  Upper 
Chalk  near  Norwich,  and  belongs  to  the  British  Museum  collection. 


Genus — Cottaldia,  Desor,  1856. 

Echinus,  pars,  Z^CBn!>,  1820;  Mimster,  1826;  Forbes,  1849.     Arbacia,  Gray,  1835. 

Cottaldia,  Desor,  1856. 

Test  small,  sub-globular,  sides  inflated,  more  or  less  depressed  at  the  poles. 
Shell  lobed,  divided  into  fifteen  sections ;  the  five  most  prominent  form  the  ambulacral, 
and  the  ten  others,  grouped  in  pairs,  the  inter-ambulacral  areas.  Poriferous  zones 
narrow,  straight ;  pores  unigeminal.  Tubercles  small,  mammillated,  imperforated, 
uncrenulated,  very  numerous,  homogeneous,  and  forming  on  each  plate  a  close-set  hori- 
zontal row.  Granules  microscopic,  placed  on  all  the  inter-tubercular  spaces.  Apical 
disc  solid,  narrow,  forming  a  prominent  ring,  composed  of  five  perforated,  rhomboidal, 
ovarial  plates,  and  five  cordate  oculars  ;  all  the  elements  of  the  disc  are  covered  with  close- 
set  granules.  Mouth -opening  moderate,  lodged  in  a  concave  depression  of  the  base ;  peri- 
stome sub-pentagonal,  decagonal,  and  feebly  notched. 

The  genus  Cottaldia  forms  a  very  natural  group  of  small  fossil  Urchins  appertaining 
to  the  Cretaceous  and  Tertiary  formations  ;  well  characterised  by  their  sub-globular  form, 
and  the  abundance  and  uniformity  of  their  tubercles,  arranged  in  horizontal  series 
over  the  entire  test.  Much  confusion  formerly  existed  between  Arbacia,  Gray ;  Echino- 
ciDARis,  Desmoulins ;  Poltcyphus,  Agassiz ;  and  Magnosia,  Michelin.  This,  however, 
has  been  in  a  great  measure  removed  by  clearer  definitions  of  the  genera  retained,  the 
suppression  of  those  that  were  doubtful,  and  the  establishment  of  the  genus  Cottaldia. 

The  uniformity  of  the  tubercles,  Prof.  Desor  remarks,  attains  its  maximum  in  this 
small  genus;  and  this  character  accords  with  its  peristome,  which  is  narrow  and  depressed, 
and  its  pores,  which  are  unigeminal  throughout  the  zones.  These  characters  distinguish 
Cottaldia  from  the  neighbouring  types  with  which  it  has  been  confounded  up  to  the 
present  time.  It  is  dedicated  by  M.  Desor  in  honour  of  his  friend  M.  Cotteau,  the 
learned  author  of  the  '  Echinides  fossiles  de  1' Yonne,'  and  of  the  '  Paleontologie  Fran^aise.' 


FROM  THE  UPPER  GREENSAND.  187 


CoTTALDiA  Benetti^,  Koiliff.     PI.  XLV,  figs.  1,  2,  3. 


EcHTNCS  BENETTI^,         Konig.     Icones  Foss.  Sectiles,  p.  2,  pi.  iii,  fig.  3,5,  1825. 

—  GRANULOSUS,    Munster,  Pet.  Germ.,  p.  125,  pi.  xlix,  fig.  5,  a.  b,  1826. 

—  —  Grateloup.     Mem.  Oursins  Fossiles,  fichiiiides,  p.  82,  1836. 
Aebacia  granulosa,      Agassiz.     Cat.  Syst.,  p.   12. 

—  —  Morris.     Cat.  of  British  Fossils,  p.  48,  1843. 

—  —  Agassiz  et  Desor.     Cat.  Rais.   des  Echinides,   Ann.   des  Sc. 

Nat,  3rd  series,  vol  vi,  p.  356. 
Echinus  granulosus,     Forbes.     Mem.  Geol.  Surv.  Organic  Remains,  Decade  I,  pi. 

vi,  1849. 

—  —  Forbes  in  Morris.     British  Fossils,  2nd  ed.,  p.  79,  1854. 
Cottaldia  granulosa,  Desor.     Synop.  des  Echinid.  Foss.,  p.  114,  pi.  xix,  fig.  1 — 3, 

1858. 

—  —  Cotteau.     Paleontologie  Fran9aise,  Ter.  Cretace,  t.  vii,  p.  789, 

pi.  1193  and  1194,  1—9,  1866. 

Diapiosis. — Test  small,  globular,  nearly  equally  depressed  at  both  poles ;  plates 
of  both  areas  very  narrow,  the  inter-ambulacral  supporting  a  horizontal  series  of  small, 
equal-sized,  imperforate,  spiniferous  tubercles,  from  eight  to  twelve  in  a  row  ;  the  ambu- 
lacral  tubercles  of  the  same  size,  less  numerous,  and  packed  obliquely  together  ;  poriferous 
zones  very  narrow,  pores  unigerainal  throughout ;  apical  disc  very  small ;  mouth-opening 
large,  placed  in  a  depression ;  peristome  slightly  decagonal,  notches  feebly  marked. 

Dimensions. — Altitude,  nine  twentieths  of  an  inch ;  latitude,  six  tenths  of  an  inch  ; 

the  relation  of  the  altitude  to  the  latitude  varies   considerably, 

some  being  more  conical,  others  more  depressed  than  others  ;  in 

four  specimens  the  ratio  was  17  to  10,  15  to  11,  12  to  11,  and 

12  to  8. 

Description. — This    beautiful   little    Urchin  was  first  figured  by  M.   Konig  in  his 

'  Icones  Fossilium  Sectiles  '  under  the  name  of  Echinus  Benettice,  in  honour  of  a  lady 

who  had  long  made  the  fossils  of  Wiltshire  her  especial  study,  and  had  published  a  valuable 

catalogue  of  the  same ;  a  year  later  the  German  forms  of  this  species  were  figured  and 

described  in   Goldfuss'   '  Petrefacta  Germanise  '  imder  Count  Minister's  name  Echinus 

granulosus ;  subsequently  it  was  entered  in  Agassiz  and  Desor's  '  Catalogue  Raisonne  des 

Echinides '    at   the  head    of  the    list   of  their  second   type    of  Arhacice  with    uniform 

tubercles  on  all  the   surface  of  the  test;  and,  lastly,   M.  Desor  established  the  genus 

Cottaldia  for  this  small  group,  which  was  characterised  by  having  the  surface  of  the  small 

test  covered   with  spiniferous  tubercles,   uniform   in  size  and  regular  in   arrangement. 


]SS  COTTALDIA. 

forming  distinct  liorizontal  rows  on  the  plates  of  the  inter-ambnlacra,   and  having  the 
pores  unigeminal  throughout  the  narrow  areas. 

The  test  varies  in  form  in  different  individuals  from  nearly  a  globular  shape,  as  in  PL 
XLV,  fig.  1,  to  forms  more  or  less  depressed  at  both  poles,  as  in  figs.  2  and  3.  The 
uniformity  in  size  and  arrangement  of  the  numerous  small  tubercles  covering  the  surface, 
and  the  division  of  the  same  into  five  broad  and  five  narrow  segments  (fig.  1  d),  by 
the  poriferous  zones  radiating  from  the  circumference  of  the  apical  disc  (fig.  1  h)  and 
converging  below  around  the  peristome  (fig.  1  c),  impart  a  remarkable  physiognomy  to- 
this  pretty  little  Urchin ;  the  medial  suture  down  the  middle  of  the  inter-ambulacra  is 
often  depressed,  and  then  Cotfaldia  Beneitia  resembles  a  little  melon,  having  its  surface 
divided  into  fifteen  lobes  (fig.  1  b,  d). 

The  ambulacral  areas  are  about  one  third  the  width  of  the  inter-ambulacral,  and  at 
the  ambitus  there  are  three  or  four  tubercles  on  each  plate  (fig.  2  h),  with  numerous  small 
granules  around  them ;  the  outer  rows  of  tubercles  are  the  most  persistent,  and  the  inner 
rows  in  general  are  limited  to  the  ambital  region  of  the  test ;  the  poriferous  zones  are  very 
narrow,  and  the  pores  numerous  and  unigeminal  throughout  (fig.  2  h)  ;  near  the  base 
they  show  a  disposition  to  fall  into  triple  oblique  pairs,  as  in  the  genus  Echinus,  but  the 
deviation  is  so  slight  that  it  is  only  occasionally  seen  in  exceptional  specimens  ;  there 
are  in  general  three  pairs  of  holes  opposite  each  ambulacral  plate  (fig.  1  e  and  fig.  2  b), 
so  that  in  the  specimen  I  am  describing  there  are  quite  100  pairs  of  holes  in  each  zone. 

The  inter-ambulacral  areas  are  three  times  as  wide  as  the  ambulacral ;  the  plates  are 
very  narrow  in  proportion  to  their  length,  and  in  the  specimen  before  me  there  are  thirty- 
five  plates  in  each  column ;  each  plate  has  a  horizontal  series  of  small  equal-sized  spini- 
ferous  tubercles ;  in  the  longest  plates  at  the  ambitus  there  are  from  nine  to  eleven  on 
each  according  to  the  age  and  size  of  the  specimen  under  examination  ;  the  tubercles  of 
both  areas  are  of  the  same  size,  but  they  are  rather  more  closely  set  together,  and  more 
obliquely  placed  in  consequence  in  the  ambulacral  areas  (see  fig.  1  e  and  fig.  2  b)  ;  the 
number  of  tubercles  in  each  vertical  row  varies  with  the  age  and  size  of  the  specimen ; 
they  are  most  numerous  near  the  ambital  region  ;  the  rows  nearest  the  poriferous  zones 
are  the  longest  and  most  persistent,  and  those  near  the  miliary  zone  the  shortest  and  most 
frequently  absent.  In  some  large  specimens  there  is  a  depression  in  the  line  of  the 
median  suture  in  the  inter-ambulacral  areas,  which  gives  this  space  a  bilobed  appear- 
ance; as  these  areas  are  nearly  half  the  width  of  the  ambulacral,  the  whole  circum- 
ference of  the  test  is  divided  by  the  five  sutural  depressions  into  ten  poriferous  zones 
and  fifteen  well-marked  lobes,  as  represented  in  fig.  1  a,  b,  c,  d,  and  this  imparts  a 
remarkable  symmetrical  neatness  to  the  physiognomy  of  the  Urchin. 

The  mouth-opening  is  nearly  circular,  and  about  one  half  the  diameter  of  the  test  (fig. 
1  c) ;  the  peristome,  which  is  superficial,  is  very  feebly  notched  opposite  the  zones. 

The  apical  disc  is  a  small  ring-like  structiu'e  slightly  projecting  from  the  surface  of 
the  test  (fig.  1   b)  ;  the  ovarial  plates  are  sub-triangular  (fig.  1  b),  and  perforated  near 


ECHINOIDEA  EXOCYCLICA.  189 

tlieir  outer  third  b}'  a  large  ovidnctal  hole ;  the  madreporiform  tubercle  is  feebly  developed 
and  occupies  the  inner  portion  of  the  right  antero^lateral  plate ;  in  most  specimens  the 
ocular  plates  are  small  and  angularly  reniforra,  the  orbit  is  excavated  out  of  the  centre  of 
their  outer  margin,  the  elements  of  the  disc  are  covered  with  numerous  small  granules, 
which  are  closely  crowded  together  on  the  surface  of  all  the  plates. 

The  test' is  extremely  thin,  and  the  spines  are  at  present  unknown. 

Affinities  and  Differences. — There  are  very  few  species  in  the  genus  Cottaldia.  C.conica, 
Agass.,  is  merely  an  elevated  form  of  C.  gramdosa ;  C.  BucJdi,  Steiniger,  is  a  nearly 
allied  species,  from  a  Tertiary  rock  at  Rommelsheim,  near  Friim. 

Loccdity  and  Stratigraphical  Position. — This  Urchin  was  formerly  very  abundant  in 
the  Upper  Greensand  of  Warminster,  and  at  Chute  Farm,  Wilts.  On  the  Continent  the  first- 
described  specimens  were  collected  at  Regensburg,  Bavaria.  In  France,  according  to  M. 
Cotteau,  it  is  found  at  Villers-sur-mer  (Calvados) ;  le  Havre,  Rouen  (Seine- Inferieure)  ; 
Yimoutiers,  La  Perriere  (Orne)  ;  La  Madeleine  (Eure) ;  le  Mans,  Coulaine,  Yvre-l'Eveque, 
les  Bordiers,  Nogent-le-Bernard,  Gaville  (Sarthe) ;  Cherves-de-Cognac  (Charente- 
Inferieure) ;  La  Bedoule  (Var)  ;  very  abundant  in  the  Etage  Cenomanien  =  Upper 
Greensand  ;  Environs  of  Royan  (Charente-Inferieure) ;  very,  rare  in  the  Etage  Senonien 
:=.  Low-er  Chalk.    . 


ECHINOIDEA  EXOCYCLICA,  Wright,  1855. 


Before  entering  upon  the  study  of  the  Echinoidea  exocyclica,  it  is  due  to  the 
Echinological  student  to  state  in  general  terms  the  reasons  that  have  led  to  the  adoption 
of  names  for  several  generic  groups  so  different  from  those  in  general  use  at  the  present 
time.  In  working  out  the  materials  for  these  Monographs  it  has  been  my  most  earnest 
endeavour  to  do  justice  to  my  predecessors  and  contemporaries  in  the  same  field  of  labour, 
by  observing  the  most  scrupulous  care  in  reference  to  priority  of  date  in  each 
genus  and  species  founded  on  figures  or  descriptions,  or  both;  without  a  rigorous 
base  of  equity  on  this  fundamental  principle,  it  would  be  vain  to  hope  for  the  stability  of 
any  sysjtem  of  nomenclature,  or  limits  to  the  interminable  list  of  synonyms  which  would 
result  from  its  neglect.  In  every  case,  therefore,  I  have  traced  back  the  history  of  each 
genus  and  species  to  its  original  author,  and  have  added  his  name  and  the  date  after 
each,  so  that  justice  is  done  to  every  naturalist  who  has  enriched  our  science  by  original 
work.     The  following  remarks  were  made  in  the  preface  to  my  Monograph  on  the  Oolitic 


190  ECIIINOIDEA  EXOCYCLICA. 

EcMnodermata,  and  twenty  years'  experience  has  only  afforded  additional  evidence  of 
their  truth. 

"  Many  of  the  readers  of  this  Monograph  will  probably  be  surprised  to  find  some  old 
generic  names  reproduced  which  have  been  long  superseded  by  those  of  modern  writers  ; 
but  a  sense  of  justice  to  such  authors  as  Van  Phelsum,  Breynius,  Klein,  and  Leske  has 
led  me  to  consult  their  original  works  and  restore  the  genera  first  described  and  figured 
by  them,  but  omitted  from  the  treatises  of  later  authors  on  the  same  subject. 

"  In  the  nomenclature  of  the  Echuiodermata,  had  I  merely  gone  back  to  the  time  of 
Linnaeus,  as  suggested  by  the  Committee  of  the  British  Association  in  their  Report  made 
in  1842.  I  must  necessarily  have  excluded  the  important  work  by  Breynius,^  in  which, 
for  the  first  time,  were  proposed  seven  well-described  and  accurately  figured  genera  of 
Uchinoidea,  which,  by  some  strange  oversight,  were  not  adopted  by  his  contemporaries, 
although  they  have  reappeared  under  new  names  in  the  works  of  later  authors.  On  the 
principle  of  priority,  therefore,  I  have  restored  the  original  genera  so  clearly  defined  by 
Breynius,  even  although  it  may  occasion  a  temporary  inconvenience  in  the  names  of  some 
well-known  forms  of  Urchins. 

"  In  every  case  where  practicable  the  name  of  the  author  who  either  first  recorded, 
described,  or  figured  the  species  follows  the  specific  name  of  the  object  without  the 
addition  of  '  Sp.'  adopted  by  some  authors.  By  this  mode  justice  is  done  to  the  original 
author  and  confusion  avoided.  The  modern  practice  of  inventing  new  generic  terms  and 
appending  to  the  old  specific  name  that  of  the  individual  who  has  merely  clianged  a 
word  but  discovered  nothing  cannot  be  sufficiently  discountenanced,  as  it  increases  the 
confusion  arising  from  an  overloaded  synonymy,  and  thereby  retards  the  real  progress  of 
the  natural-history  sciences."'' 

The  first  author  who  described  systematically  and  figured  accurately  many  typical 
forms  oiEchinidm  was  undoubtedly  Breynius,'  in  his  '  Schediasma  de  Echinis  ;'  he  takes 
the  general  form  of  the  test  and  relative  position  of  the  vent  as  the  basis  of  his 
methodical  arrangement,  in  which  he  groups  the  whole  order  into  the  seven  following 
genera. 


I.   Genus — Echinometra,  Breynius,  1732. 

Shell  more  or  less  globular,  the  mouth  and  vent  occupying    the  two  poles.     This 
genus  was  retained  by  Gaultieri,  1742  ;  by  Seba,  1758,  and  by  Van  Phelsum,  1770 ;  but  it 

'  De  Echinis  et  Echinitis,  sive  methodica  Echinorum  distribiitione,  Schediasma.     Gedani,  1/32. 
2  'Monograph  on  the  British  Fossil  Echinodermata  of  the  Oolitic  Formation,'  p.  vii.  Pal.  Soc.  vol.  for 
18.55. 

8  Joannis  Phillippi  Breynii  dissertatio  physica  de  Polythalamiis— tanderaque  Schediasma  de   Echinis 
niethodiee  disponendis  cum  figuris.     Gedaui,  1732. 


BREYNIUS'  GENERA.  191 

was  changed  into  Cidaris  by  Klein,  in  1734,  into  Echiiiushy  Linnseus,  in  1758,  and  into 
Echinus  and  Cidaris  by  Lamarck  in  1801,  who  suppressed  the  name  Echinometra 
altogether.  It  has  been  restored  to  another  group  of  Urchins  by  Agassiz  in  1846, 
who  unfortunately  attributed  the  name  to  Klein  instead  of  Breynius  its  author. 


II.  Gemis — EcHiNOCONUs,  Breynius,  1732. 

The  mouth  in  the  centre  of  the  base,  and  the  vent  beneath,  at  the  margin,  or  above 
the  border ;  the  shell  elevated,  round,  or  conoidal.  This  generic  name  was  ignored  by 
Klein,  1734,  who  changed  it  to  Conulus ;  Leske,  his  commentator  in  1778,  changed  it  to 
EcMnites.  Lamarck,  1801,  omitted  the  names  proposed  by  his  predecessors,  and  gave 
that  of  Galerites  to  the  same  group;  all  the  authors  down  to  the  time  of  Alcide 
d'Orbigny  have  followed  Lamarck  instead  of  Breynius,  who  nearly  a  century  before 
had  well  described  and  figured  this  genus. 


III.  Genus — Echinocorys,  Breynius,  1732. 

* 

The  test  is  helmet-shaped,  with  the  mouth  and  vent  beneath,  the  former  aperture 
before,  and  the  latter  at  the  marginal  border.  This  generic  name  was  ignored  by  Klein  and 
changed  by  him  to  Galea  in  1734.  It  was  retained  by  Leske,  1778,  by  Parkinson,  1811, 
and  Mantell,  1832.  Lamarck  in  1801  proposed  the  new  name  Ananchytes  for  this  group, 
which  was  retained  and  adopted  by  all  subsequent  modern  authors  down  to  1853,  when 
d'Orbigny  restored  to  this  form  Breynius'  original  name  Echinocorys. 


IV.   Gettus — EcHiNANTHDs,  Breyuius,  1732. 

Large,  oblong,  shield-shaped  Urchins  with  petaloidal,  ambulacral  areas ,  the  mouth- 
opening  beneath  near  the  centre,  and  the  vent  within  or  below  the  marginal  border  ;  this 
genus  was  preserved  by  Gaultieri,  1742,  and  Leske,  1778.  It  was  changed  into  Scutum 
by  Klein,  1734;  into  Clypeaster  by  Lamarck,  1816;  and  into  Echinolamjjas  by  Gray  in 
1834.  Agassiz  and  most  other  modern  authors  retained  the  name  Echinolampas  until 
d'Orbigny  rightly  restored  the  old  original  name  Echinanthiis  to  all  oblong  Urchins  with 
leaf-shaped  ambulacra  and  the  vent  in  the  lower  border. 


193  BREYiNIUS'  MEMOIR 


V.  Genus — Echinos-patagus,  j8irey«2«s,  173i2. 

Heart-shaped  Urchins,  with  inflated  sides,  the  ambulacra  on  the  upper  surface  lodged 
in  depressions  of  the  test;  the  mouth  anterior  between  the  centre  and  tlie  border;  the 
vent  on  the  upper  part  of  the  posterior  border  in  a  direction  oblique  to  that  of  the 
mouth.  This  name  was  changed  by  Klein,  1734,  to  7§?fl/««^MS,  adopted  by  Lamarck 
and  all  subsequent  authors.  As  the  genus  Echinospatagm  represents  a  natural  family 
rather  than  a  genus,  one  of  the  forms  figured  by  Breynius  among  his  types  ought  to 
bear  this  generic  name,  whilst  the  other  genera  might  be  readily  arranged  around  the 
central  type  form. 


VI.   G^KS— EcHiNOBRissus,  Brepiius,  1732. 

Small  buckler-shaped  Urchins  more  or  less  depressed,  the  mouth-opening  near  the 
centre  of  the  base,  vent  debouching  into  a  deep  dorsal  sulcus,  ambulacral  areas  petaloidal. 
The  specimen  figured  as  the  type  of  this  genus  is  one  of  the  most  common  Oolitic  forms. 
Still  no  author  has  cited  this  genus,  and  it  appears  to  have  been  overlooked  until  Lamarck 
described  it  under  the  name  Nucleolites. 


VII.   Genus — Echinodiscus,  _5rej/wzas,  1732. 

Discoidal  Urchins  with  the  mouth  and  vent  opening  near  each  other  at  the  base. 
The  ambulacra  limited,  petaloidal,  and  dorsal.  Shell  always  flat ;  border  thin,  entire,  or 
often  indented  or  perforated.  This  genus  was  adopted  by  Gaultieri,  1742,  and  by  Seba, 
1758;  by  Leske  and  Davila,  1778.  It  was  changed  to  Botula  by  Klein,  1734,  and  into 
Scutella  by  Lamarck,  1801. 

The  '  Dissertatio  Physica  de  Polythalamiis,  de  Belenmitis,  de  Echinis,'  by  Breynius,  is 
a  very  scarce  book.  After  endeavouring  in  vain  to  obtain  it  in  commerce,  I  made  known 
my  want  to  my  friend  Professor  de  Koninck,  of  Liege,  who  kindly  gave  me  the  copy  I 
now  possess.  In  discussing  many  years  ago  the  merits  of  this  work  with  my  old  friend 
the  Rev.  Robert  Hepworth,  M.A.,  he  kindly  offered  to  make  a  translation  for  my  Mono- 
graph of  that  portion  of  the  dissertation  which  related  to  the  classification  of  the  Ecldno- 
dermata,  for  which  I  heai-tily  thank  him,  and  I  have  now  the  pleasure  of  adding  the 
version  as  it  came  from  his  pen.  I  have  inserted  such  references  to  the  plates  of  this 
Monograph  as  will  help  the  reader  to  supply  the  absence  of  the  original  plates  which 
accompany  the  work  of  Breynius. 


DE  ECHINIS.  193 


"  De  ECHINIS   ET  ECHINITIS,  SIVE  METHODICA  EcHlNORUM  DiSTRIBUTIONE,  ScHEDIASMA 

JoANNis  Philippi  Breynii,  M.D.,  ET  SociET.  Reg.  Lond.  Sodalis." 


"  Genus  I. — The  Echinometra  is  an  Echinus  with  the  oral  aperture  placed  in  the  centre 
of  the  base,  hut  icith  the  anal  one  diametrically  opposite  at  the  summit. 

The  term  Echinometra  occurs  in  Aristotle,  who  designates  by  it  the  largest  genus  of 
Echini.  Naturalists  dispute  whether,  on  this  point,  regard  must  be  had  to  the  size  of 
the  spines,  or  of  the  test.  Bellonius  and  his  followers  determine  the  latter.  Hence  I 
think  that  this  name  is  not  inappropriately  affixed  to  this  Echinus,  since  those  belonging 
to  this  genus  are  found  equal  in  size  to  an  infant's  head.  There  is  this  additional 
peculiarity,  that  this  genus,  among  all  the  Echini,  is  provided  with  very  large  spines  and 
tubercles.     Its  common  name  is  Ovarius. 

The  Echinometra  has  many  peculiarities  which  distinguish  it  from  other  Echini, 
besides  the  position  of  the  apertures. 

1.  Internally  there  are  five  testaceous  teeth,  each  elaborately  composed  of  several 
parts,  and  surrounded  by  testaceous  semicircles,  which  are  situated  internally  around  the 
oral  aperture.  Some  species  of  Echinanthus  are  also  furnished  with  teeth,  but  of  a 
different  structure. 

2.  The  test  is  divided  into  five  equal  or  nearly  equal  areas. 

3.  Externally  it  is  rendered  rough  by  tubercles,  greater  or  smaller  according  to  regular 
series,  placed  for  the  purpose  of  receiving  the  sockets  of  the  spines ;  whilst  in  the  other 
Echini  all  the  tubercles  are  nearly  equal  in  size  and  very  small. 

4.  In  like  manner  it  has  the  primary  and  secondary  spines  more  or  less  large  and 
unequal  in  size,  whilst  all  the  spines  of  other  Echini  are  very  small,  and  generally  of 
equal  size. 

5.  I  have  also  especially  observed  near  the  anal  aperture  a  small  warty  substance  [the 
madreporiform  body],  which  can  be  more  clearly  distinguished  with  a  lens,  and  similar  to 
that  which  Linck  first  detected  in  the  Star-fish,  the  use  of  which  in  that  animal  will 
doubtless  throw  light  also  upon  this  species  of  the  Echinometra." 

[Plates  V  and  VI  of  this  work  represent  typical  forms  of  this  group.] 


25 


194  SCHEDIASMA 


"  Genus  II. — The  Echinoconus  ii  an  Echinus,  whose  ajiertures  are  lofh  in  the  base,  the 
oral  in  the  centre,  and  the  anal  at  or  in  the  mar(ji7i. 

It  is  either  of  a  conical  figure  (the  Echinites  pileatus  of  Luidius),  or  hemispherical,  or 
more  or  less  compressed  or  oval.  All  of  them  have  five  duplicate  pointed  Unes 
extending  from  the  vertex  to  the  oral  aperture. 

I  have  observed  various  fossil  species  of  this  genus,  but  only  one  recent  species. 

I  have  given  it  the  name  of  Echinoconus  from  the  conical  figure  which  certain 
species  possess. 

Table  II,  fig.  1. — The  Echinoconus  vere  conicus  ;  perfectly  conical,  fossil;  filled 
with  cretaceous  matter.  From  the  Kent  chalk  pits.  The  Echinites  pileatus,  with  either 
a  conoid  figure,  or  somewhat  turbinated.     [Plates  XLIX  and  L  of  this  work.] 

Pig.  2.  The  base  of  the  same,  in  which  may  be  observed  the  oral  aperture  in  the 
centre  and  the  anal  in  the  margin.     [Plate  L,  fig.  1.     Echinoconus  conicus,  Brey.] 

Fig.  3.  The  Echinoconites  hemisph^ricus  ferme,  nearly  hemispherical,  consisting 
of  siliceous  matter,  or  of  what  is  commonly  called  hornstoue.     [Plate  LIII,  fig.  2  c,  (/.] 

Fig.  4.  The  base.     [Plate  LIII,  fig.  2  b.     Echinoconus  subrotundus.'] 

Fig.  5.  Echinoconus  ovalis,  the  anal  aperture  near  the  margin.  This  is  the  only 
recent  one  known  to  me ;  it  does  not  exceed  half  an  inch  in  size,  is  fragile,  and  with  a 
whitish  shell. 

Fig.  6.  The  base. 


Genus  III. — The  Echinocorys  is  an  Echinus  with  both  ajjertures  in  the  base,  the  oral 
between  the  centre  and  the  margin,  and  the  anal  as  distant  as  possible  from  the 
moicth  in  the  margin  itself. 

All  those  which  have  come  under  my  observation  approximate  in  some  measure  in 
their  form  to  that  of  a  helmet.  Hence  they  are  termed  by  Luidius  in  his  'Litho- 
phylacium  Britanuicum  '  galeati  or  helmeted. 

I  have  designated  the  genus  Echinocorys  for  the  same  reason,  as  Kopuc  among  the 
Greeks  signified  a  helmet  or  casque.  Hitherto  I  have  observed  no  recent  specimen  of 
this  genus,  but  many  fossil  ones. 

Table  III,  fig.  1.  The  Echinocorys  vulgaris  ;  fossil,  filled  with  cretaceous  matter, 
from  the  chalk  pits  near  Gravesend,  Kent.  This  is  the  common  helmeted  Echinites 
of  Luidius. 

Fig.  2.  The  base  of  the  same,  with  two  apertures;  the  upper  one  is  the  mouth,  the 
lower  the  anus." 


DE  ECHINIS.  195 

"  Fig.  3.  The  Echinocoryta,  like  marble,  ashy  grey,  representing  with  the  greatest 
exactness  the  internal  face  of  the  shell.      [This  is  a  siliceous  mould  of  an  EcJdnoconus.'] 
Fig.  4.  The  base.     [Siliceous  mould  of  the  base  of  a  small  Echimcorys  vulgaris?^ 


Genus  IV. — The  Echinanthus  is  an  EcMnus  toJiose  oral  aperture  is  near  the  centre, 
and  the  aiial  vpon  or  at  that  part  of  the  margin  iohich  is  at  the  greatest  distance 
from  the  oral. 

All  the  species  of  this  genus  have  an  oval  figure,  one  extremity  of  which  is  narrower, 
the  other  broader,  in  which  latter  the  anal  aperture  is  always  situated ;  but  the  poriferous 
zones  in  the  upper  surface  resemble  a  five-petaled  flower,  as  though  they  were  artificially 
marked  by  a  needle ;  and  for  this  reason  I  have  assigned  to  this  genus  the  name  of 
Echinanthus  or  Urchin  flower. 

It  is  termed  by  Woodward  Echinus  pentaphglloides,  i.  c.,  five-leaved,  and  is  repre- 
sented as  having  only  one  foramen  in  the  centre  of  the  base ;  whereas,  on  the  contrary, 
the  other  foramen  is  conspicuous  upon  or  at  the  margin  in  both  the  fossil  and  the  recent 
species. 

Fig.  1.  The  Echinanthus,  with  the  vertex  (upper  surface)  more  or  less  raised,  of  a 
whitish  colour.  F>om  the  Kleinian  Museum.  This  species  seems  to  approximate  in  the 
outward  shape  of  an  helmet  to  the  Echinocorys,  but  it  differs  from  it  sufficiently  in  the 
position  of  the  mouth,  and  in  the  likeness  of  the  flower  at  the  summit. 

Kg.  2.  The  base.  This  fossil  Echinanthus,  filled  with  chalky  matter,  is  depicted  in 
the  '  Museum  Amboinse,'  Tab.  LIX,  fig.  d. 

Fig.  3.  An  Echinanthus  of  flatter  form  ;  fossil ;  filled  with  stony  matter.  From  Monte 
Baldo,  near  Verona ;  remarkable  for  the  upper  surface  Avith  the  anal  aperture. 

Fig.  4.  An  Echinanthus  with  the  dorsal  region  more  or  less  raised  along  its  length ; 
fossil ;  filled  with  stony  matter  of  an  ashy  colour. 

Fig.  5.  The  base.  The  oral  aperture  near  the  centre,  the  anal  on  the  margin.  In 
this  genus  the  anal  aperture  is  generally  so  situated  that  it  can  be  viewed  equally  well 
from  both  the  summit  and  the  base.  On  this  account  I  am  the  more  astonished  that 
Woodward  should  have  overlooked  it." 

[Plate  LVIII,  Pygurus  lampas,  represents  a  type  form  of  this  genus.] 


196  SCHEDIASMA 


"Genus  V. — The  Echinospatagus  is  an  Echinus  lohose  oral  aperture  is  between  the  centre 
and  the  margin,  but  the  anal  is  situated  obliquelj)  oj^iposite  to  the  mouth  upon  or 
at  the  margin  towards  the  summit. 

The  figiu-e  is  usually  heart-shaped,  the  furrow  being  on  the  upper  surface  at  the  broader 
extremity ;  or  it  is  oval  without  a  furrow  of  that  kind.  But  the  anal  aperture  is  always 
observable  in  the  narrow  extremity,  as  in  the  Echinanthus.  In  some  species  there  is  also, 
it  appears,  some  representation  of  a  flower,  as  in  my  Echinanthus,  but  this  consists  not  of 
fve  but  of  only/o?(!r  petals,  and  those  of  unequal  size ;  the  fifth  towards  the  broader 
extremity  being  absent. 

1  have  thought  that  the  name  of  Sjxitaf/us  or  Spatancjus,  derived  from  the  Greek 
Swarayyoc,  and  which  is  found  in  Aristotle  and  other  naturalists  who  have  thus  desig- 
nated this  Echinus,  ought,  on  this  account,  to  be  retained,  although  more  recent  writers 
have  extended  the  terra  Spatagus  or  Spatanc/us  to  all  except  the  oval  Echini ;  and  these 
Woodward  also  has  followed  in  his  catalogue,  which  embraces  under  this  title  all  except 
the  oval  and  those  marked  with  five  leaves — the  pentaphylloidal  shaped. 

Table  V,  fig.  1. — The  Echinospatagus  cordiformis  ;  very  common.  The  anal 
aperture  which,  in  the  entire  shell,  is  usually  closed  l^ecause  it  is  membranous,  does  not 
seem  to  be  less  minute  than  in  the  oval.  I  have  found  the  shells  of  this  genus  empty, 
blanched,  and  very  fragile.  They  are  very  commonly  found  on  the  shores  of  the  Adriatic, 
near  Pesaro,  where  they  are  termed  Cut/lioni  on  account  of  their  shape  and  size. 

Fig.  2.  The  base,  in  which  may  be  observed  both  the  oral  aperture  and  the  anal  one 
of  less  size. 

Fig.  3.  The  heart-shaped  Echinospatagus,  more  or  less  flat,  of  a  smaller  size ;  fossil ; 
filled  with  chalk  rock  ;  from,  I  believe,  Wirtemberg.    Fig.  4.  The  base. 

Fig.  5.  The  heart-shaped  Echinospatagus ;  fossil.  English,  from  the  Kent  chalk  pits. 
The  Echinites  cordatus  of  Luidius.     [See  Plate  LXII,  Micraster  cor-anguinum?\ 

Fig.  6.  The  base.    [Plate  LXII,  fig.  1  5.] 


Genus  YI. — The  Echinobrissus  is  an  Echinus  whose  oral  aperture  usually  occupies  the 
centre  of  the  base,  but  the  anal  is  seen  upon  the  upper  surface  at  a  short  distance 
from  the  centre,  and  in  a  furrow  obliquely  opposite  to  the  mouth. 

It  is  always  of  an  oval  shape,  with  the  mouth  invariably  placed  towards  the  narrower 
and  the  anus  towards  the  broader  part.  Some  species  are  rather  more  elevated,  and 
represent  in  some  measure  the  human  buttocks  ;  hence  it  is  called  clunicularis  by  Luidius : 


.  DE  ECHINIS.  197 

but  others  with  a  flatter  surface  may  be  compared  to  a  shield ;  hence  they  are  termed 
Echini  clypeati. 

The  Brissus  (Bpfo-trog)  is  enumerated  by  Aristotle  in  his  fifth  book  of  the  '  History 
of  Animals  '  as  the  tJiird  genus  of  Echini.  But  since  his  translators  have  not  sanctioned 
what  this  naturalist  understood  by  that  term,  I  have  applied  the  name  of  Brissus  to  this 
genus. 

No  recent  Echinobrissus  has  come  under  my  observation,  but  I  have  seen  some  fossil 
species,  although  these  latter  are  by  no  means  common.  Morton  assigns  only  one  aperture 
to  this  Echinus,  since  the  other  situated  in  the  furrow  escaped  his  notice ;  but  Woodward 
ought  afterwards  to  have  discovered  it,  since  he  enumerates  it  among  the  Echini  which 
have  two  apertures,  the  other  being  in  the  furrow. 

Table  VI,  fig.  1.  The  Echinobrissus  planior  or  Clypeatus  minimusj  fossil;  filled 
with  stony  matter ;  with  the  anal  aperture  in  the  furrow.  From  England.  [Echino- 
brissus  clunicularis.'\ 

Fig.  2.  The  base  with  the  oral  aperture. 

Fig.  3.  Echinobrissus  ELATIOR  ;  more  or  less  raised ;  fossil;  filled  with  stony  matter. 
From  England.     [Echinobrissus  scutatus,  a  characteristic  fossil  of  the  Coralline  Oolite.] 

[Plate  LVI,  figs.  1  and  2  represent  several  type  forms  of  Echinobrissi  from  the  Creta- 
ceous formations.     This  genus  has  one  living  representative  species.] 


Genus  VII. — The  Echinodiscus  is  an  Echinus  with  the  oral  aperture  situated  near  the 
centre,  but  ivith  the  anal  between  the  centre  and  the  margin  or  on  the  margin. 
The  form  always  somewhat  flattened. 

All  the  species  of  this  genus  have  the  likeness  of  a  five-leaved  flower  upon  the  upper 
surface. 

I  have  termed  it  Echinodiscus  from  the  figure  of  a  disc  or  orb. 

As  I  have  not  seen  any  recent  Echinus  of  the  genus  iumiediately  preceding,  so,  on  the 
other  hand,  I  have  never  hitherto  observed  a  fossil  of  this  genus.  The  foUowing  species 
were  all  brought  from  the  Eastern  Ocean. 

Table  VII,  fig.  1.  The  Echinodiscus  circinatus  minor,  with  the  margin  entire. 

Fig.  2.  The  base  or  lower  portion,  in  which  is  seen  the  anal  aperture,  but  the  other 
(the  oral)  in  the  middle  is  not  visible  on  account  of  the  mutilation  of  the  shell  in  the 
centre. 

Fig.  3.  Echinodiscus,  one  half  of  the  circumference  generally  marked  with  equal 
indentations. 

Fig.  4.  The  base,  in  which  are  seen  the  oral  and  anal  apertures." 


198  ECHINOCONIDtE. 

"Fig.  5.  All  EcJiinodiscus,  one  half  of  the  circumference  marked  with  unequal  indenta- 
tions.    The  other  half  furnished  with  two  pervious  apertures. 

Fig.  0.  The  base,  with  mouth  and  anus. 

Fig.  7.  The  Echinodiscus  aiaximus,  with  margin  entire.  The  anal  aperture  placed 
on  the  margin  itself.     From  the  Kleinian  Museum. 

Fig.  8.  The  base,  with  the  oral  aperture  in  the  centre. 

A  new  genus  may  not  inaptly  be  constituted  as  the  eighth  in  order  in  my 
'  System,'  from  this  last  species,  since  it  differs  as  to  the  rule  of  the  position  of  the  anal 
aperture,  and  in  the  absence  of  the  representation  of  the  flower.  But  since  only  this 
single  species  has  been  known  hitherto,  I  have  preferred  adding  it  to  the  EcJiiuodisci, 
until  perchance  some  other  specimen  shall  have  been  discovered." 

[I  must  refer  all  interested  in  the  study  of  this  group  to  Professor  L.  Agassiz's 
admirable  Monograph  '  Des  Scutelles,'  with  magnificent  plates  of  living  and  fossil  forms. 
T.  W.] 


VI.  Famili/ — Echinoconid^,  Wright,  1854. 

^Vlien  I  proposed  the  establishment  of  this  Family  I  defined  it  as  a  natural  group  of 
fossil  Eclihioidea  having  a  thin,  circular,  or  slightly  pentagonal  test ;  the  upper  surface 
in  most  of  the  forms  being  very  much  elevated  or  conoidal,  in  others  it  is  more  or  less 
depressed. 

The  ambidacral  areas  are  narrow  and  the  inter-ambulacral  wide  ;  the  plates  of  both 
are  covered  with  numerous,  small,  perforated  tubercles,  raised  on  bosses  with  crenulated 
summits.  They  are  sometimes  scattered  over  the  plate,  but  are  frequently  arranged  in 
regular  longitudinal  rows.  They  are  always  larger  at  the  base  than  on  the  sides  and 
dorsum ;  and  the  surface  of  the  test  is  likewise  covered  with  close-set  microscopic 
granules. 

The  poriferous  zones  are  narrow,  and  formed  throughout  of  round  unigeminal  pores 
about  equal  in  diameter;  they  converge  in  a  straight  line  from  the  apical  disc  to  the 
peristome,  around  which  aperture  they  have  sometimes  a  bigeminal  arrangement. 

The  mouth-opening  is  inferior,  central,  sub-circular,  and  armed  with  five  pairs  of  jaws ; 
the  peristome  is  more  or  less  decagonal  and  divided  by  notches  into  ten  lobes,  well 
marked  in  Pijcjaster  and  Holed i/jms,  but  feebly  in  Discoidea  and  Echinoconus. 

The  vent  is  variable  in  position ;  it  is  situated  at  the  upper  surface  in  Py(jaster,  at  the 
border  in  Echinoconus,  at  the  base  in  Discoidea ;  and  this  "aperture  is  oval,  pyriform,  or 
oblique  in  different  genera. 

The  apical  disc  occupies  the  summit  of  the  upper  smface,  and  is  composed  of  five  ovarial 
and  five  ocular  plates ;  the  madreporiform  body  is  very  large,  extending  from  the  right 
antero-lateral  ovarial  into  the  centre  of  the  disc. 


ECHINOCONID^.  199 

The  posterior  ovarial  is  often  replaced  by  a  complementary,  imperforate  plate,  which 
is  sometimes  wanting  altogether. 

The  spines  are  small,  short,  and  subulate. 

The  EcHiNocoNiDyE  are  distinguished  from  the  Echinobrissid.e,  Echinolampid^, 
and  Clypeasterid^,  by  their  simple  poriferous  zones ;  in  this  respect  the  family 
resembles  the  Echinonid^,  from  which,  however,  it  differs  in  possessing  a  peristome 
furnished  with  auricles  and  a  masticating  apparatus ;  the  form  is  likewise  more  circular 
and  elevated,  and  the  tubercles  are  more  developed  and  arranged  in  longitudinal  rows. 

The  EchinoconiDjE  are  an  extinct  family,  found  only  in  the  Oolitic  and  Cretaceous 
rocks;  at  present  we  recognise  six  well-defined  genera  in  this  natural  group,  which 
present  the  following  opposite  characters : 

Test   elevated ;    ambitus   with   projecting   internal   septa ;    vent 

inferior  always     .....     Discoidea. 

Test  elevated  ;  peristome  sub-decagonal ;  vent  marginal  .     Echinoconus. 

Test   depressed ;    ambitus  without  internal  septa ;   vent  inferior 

and  marginal       .....     Holectypus. 

Test  depressed  ;  peristome  decagonal ;  vent  oblique,  distant  from 

the  disc ;  tubercles  perforated  and  crenulated       ,  .     Anorthopygus. 

Test  depressed ;  peristome  decagonal ;  vent  pyriform,  separated 
from  the  disc;  tubercles  perforated,  but  not  crenulated; 
irregularly  superposed  pores  .  .  .     Pileus.    • 

Test  depressed ;  peristome  decagonal;  vent  pyriform,  not  separated 
from  the  disc ;  tubercles  perforated  and  not  crenulated ;  pores 
xmigeminal,  regularly  superposed  .  .  .     Pygaster. 


I.  Gemis — Discoidea,  Klein,  1734. 

Galekites,  pars,  Lamarck,  1801.     Discoidea,  Gray,  1834.     Discoidea,  Agassiz,  1836. 

Discoidea,  Desor,  1842. 

Test  circular  or  subpentagonal  at  the  border ;  upper  surface  much  elevated,  hemi- 
spherical ;   sides  vertical  or  slightly  convex  ;  inferior  surface  flat,  slightly  concave. 

Poriferous  zones  very  narrow,  and  converging  in  a  straight  line  from  the  disc  to  the 
peristome. 


200  DISCOIDEA. 

Tubercles  very  small,  perforated,  creniilated,  and  surrounded  by  areolae,  unequal  and 
microscopic  on  the  sides  and  upper  surface;  larger  at  the  ambitus  and  base,  and  disposed 
there  in  regular  concentric  rows. 

Mouth-opening  small,  circular,  central ;  peristome  decagonal,  marked  by  slight  notches. 

Vent  inferior,  oval,  sub-acuminate  at  both  extremities,  situated  between  the  peristome 
and  posterior  border;  opening  covered  with  irregular  granular  plates,  which  are  very 
small  around  the  anal  opening ;  this  aperture  is  placed  near  the  internal  angle. 

The  apical  disc  solid,  well  soldered  to  the  areal  plates,  and  forming  a  slight  projection 
above  the  test,  having  in  some  five  perforated  ovarial  plates,  in  others  four  perforated 
ovarials,  and  an  imperforate,  complementary,  single  ovarial ;  raadreporiform  body  resting 
on  the  larger  antero-lateral,  and  extending  into  the  centre  of  the  disc ;  ocular  plates  small 
and  well  wedged  into  the  angles  of  the  ovarials. 

From  the  inner  surface  of  the  inter-ambulacral  plates  near  the  poriferous  zones  thick 
shelly  processes  project  inwards,  and  form  internal  septa,  which  occasion  the  ten  charac- 
teristic impressions  near  the  ambitus  seen  on  the  moulds  of  this  genus. 

Spines  short,  stout. 

The  Biscoidea  very  much  resemble  Holedijpus.  Prof.  Desor  properly  separated 
the  latter  from  the  former  in  consequence  of  the  absence  of  all  internal  ribs  from  the  shell 
of  Holectypus,  which  likewise  has  a  larger  mouth-opening,  the  peristome  deeper  notched, 
and  the  vent  often  marginal. 


o 


A. — Species  from  the  Upjjer  Greenscmd. 
DiscoiDEA  SUBUCULUS,  Klein,  1734.     Plate  XLV,  figs.  4,  5,  6. 

DiscoiDES  SUBUCULUA,  Klein.     Nat.  dispositio  Echinodermatum,  p.  26,  pi.  xiv, 

I,  m,  1734. 
EcHiNiTES  SUBUCULUS,  Leslce,  apud  Klein,  p.  171,  pi.  xiv,  /,  ?n,  n,  o,  1778. 

—  —  Gmelin.     Systema  Nature,  p.  3183,  1789. 

—  — ■■  Encyclop.  metliod.,  Moll,  et  Zoophyt.  Atlas,  pi.  158,  figs. 

14,  15,  1791. 
DiscoiDEA  SUBUCULUS,  JBarkinsoH.     Organic  Eemains,  toI.  iii,  p.  21,  1811. 

EcHiNiTES,  Smith.     Strata  Ident.   by  Organ.   Foss.,  pi.  vii,  fig.    12, 

1816. 
Galekites  kotulaeis,  Lamarck.     Animaux  sans  Yert.,  t.  iii,  p.  21,  181 1. 

—  —  Deslongchamps.     Zoopb.,   Encyl.  method.,  t.   ii,  p.  433, 

1824. 

—  —  Befrance.     Galerites,  Die.  Sc.  Nat.,  t.  xviii,  p.  86,  1825. 
Galerites  SUBUCULUS,  Goldfuss.     Petref.  Germanise,  t.   i,  p.    129,  pi.  xlix,  fig.  2, 

1826. 
EcHiNONEUS  KOTULARis,        BlainvUle.     Zoopb.,  Die.  Sc.  Nat.,  t.  Ix,  p.  194,  1830. 
DiscoiDEA  SUBUCULUS,  Bronn.     Lethsea  Geogn.,  p.  615,  pi.  xxix,  fig.  19,  1835. 

—  ROTULAKis,  Agassi:.     Prodrome  d'une  Monogr.,  p,  186,  1836. 


FROM  THE  UPPER  GREENSAND.  201 

Galerites  hemisph^eeicus,  Grateloup.     Mem.  les  Oursins  Fossiles,  p.  55,  1836. 

—  sxTBCCULUs,         Besmoulins.    fitudes  sur  les  Echinides,  p.  254,  1836. 
DiscoiDEA  STJBUCULUS,  Besor.     Monogr.  des  Galerites,  p.  54,  pi.  vii,  figs.  5 — 7, 

1842. 

—  —  Morris.     Catalogue  of  British  Fossils,  p.  52,  1843. 

—  —  Agassi:  and  Desor.     Catal.  rais.  des  Ech.,  Ann.  Sc.  Nat. 

3e  serie,  t.  vii,  p.  146,  1847. 

—  —  A.  Gras.     Oursins  fossiles  de  I'lsere,  p.  44,  1848. 

—  —  Bronn.     Index  Palseontologicus,  p.  430,  1848. 
Galerites  subuculus,  Forbes.     Mem.  Geol.  Surv.,  Dec.  1,  pi.  vii,  1849. 
DiscoiDEA  SUBUCULUS,  d'Orbigny.     Prod,  de  Pal.  Strat.,  t.  ii,  p.  179,  1850. 

—  —  Sorignet.     Oursins  fossiles  de  I'Eure,  p.  39,  1850. 
Galerites  subuculus,  Forbes  in  Dixon's  Geology  of  Sussex,  p.  341,  1852. 
DiscoiDEA  SUBUCULUS,  Forbes    in  Morris's  Catalogue  of  Brit.   Fossils,   2ud  ed., 

p.  77,  1854. 

—  —  Desor.      Synop    des    Echinides  Foss.,  p.   1/6,  pi.   sxiv, 

fig.  1,  1857. 

—  —  Cotteau    and  Triger.      Ecliinides   Foss.    de    la    Sarthe, 

p.  170,  pi.  xxiv,  fig.  12,  1859. 

—  —  Cotteau.     Paleontologie  Fran^aise,  Ter.  Cretace,  t.  vii,  p. 

23,  pi.  1009,  fig.  8—16,  1864. 

—  —  Be  Loriol.     Oursins  de  la  Suisse,  pi.  xiii,  fig.  15,  1873. 

Dict(/)iosis. — Test  small,  circular,  or  slightly  pentagonal ;  upper  surface  inflated,  more 
or  less  conical ;  under  surface  concave  in  the  middle ;  ambulacra  forming  five  prominent 
bands,  composed  of  very  narrow  plates ;  poriferous  zones  narrow,  straight,  holes 
imigeminal  in  oblique  pairs.  Interambulacra  wide,  divided  into  three  lobes  by  two  sub- 
central  carinse,  which  rise  from  near  the  middle  of  the  plates ;  miliary  zone  concave, 
depressed ;  tubercles  small,  perforated,  larger  at  the  base ;  on  the  sides  there  are  two 
regular,  constant,  carinal  rows,  and  eight  or  ten  less  regular  and  inconstant ;  at  the  base 
the  principal  tubercles  are  arranged  in  concentric  lines  around  the  peristome.  Surface  of 
all  the  plates  covered  with  fine  close-set  granulations  ;  mouth-opening  small,  sunk  in  the 
middle  of  a  deep  depression;  vent  infra-marginal,  pyriform,  midway  between  the 
peristome  and  border,  with  the  apex  directed  inwards.  Apical  disc  small,  prominent, 
composed  of  five  ovarial  and  five  very  small  ocular  plates. 

Bimensions. — Height,  seven  twentieths  of  an  inch  ;  latitude,  eleven  twentieths  of  an 
inch.  The  relative  proportion  of  height  to  breadth  varies  considerably  in  different 
specimens. 

Description. — A  figure  given  by  Plott^  in  his  '  History  of  Oxfordshire,'  pi.  viii,  fig.  9, 
and  described  as  "another  sort  of  Button-stone,  sent  me  from  Teynton,  which  I  take  to  be 
a  mere  production  of  nature,  finely  striated  from  the  top,  as  I  have  seen  some  hair  buttons, 
as  in  Eig.  9,  and  may  therefore  be  called  Porpites .-  except  we  should  rather  take  it  for  a  new 
sort  of  EcJdnites  not  yet  discovered,  which  is  wholly  left  to  the  reader's  choice."     Martin 

>  '  The  Natural  History  of  Oxfordshire,'  ed.  1677,  pi.  viii,  fig.  9,  p.  139. 

26 


202  DISCOIDEA 

Lister'  in  his  '  Hist.  Animal.  Angliae '  states,  in  reference  to  his  fig.  20,  tab.  vii,  which  is 
copied  from  Plott,  "  Echinites  parvulus  striis  capillaceis  undiq ;  insignitus,"  ex  D.  Plott, 
fig.  9,  tab.  viii,  "  Juxta  Teynton  agri  Oxoniensis  inventus  est." 

Lang,2  in  his  '  Historia  Lapidum  Figm-atorum,'  says,  in  reference  to  "  Echinites,  striis 
capillaceis  a  centro  ad  circumferentiam  undique  insignitus,  subluteus  mediocris  rotundus, 
vertice  compresso,  basi  ex  pluribus  annuUs  striatis  sibi  invicem  impositis  conflata."  I 
regard  the  original  of  Plott's  figure  not  as  an  Echinite,  but  as  a  species  of  Coral  belonging 
to  the  family  Ci'CLOLiTiDiE,  genus  Anabacia;  about  Lang's  figure  I  think  there  can  be  no 
doubt,  the  concentric  ridges  of  the  epitheca  at  the  base  afford  sufficient  evidence  of  the 
class  Anthozoa  to  which  his  fossil  Coral  belonged.  Klein's  '  Naturalis  Dispositio  '  is  the 
first  work^  in  which  we  find  an  undeniable  figure  of  this  Urchin ;  in  tab.  xiv,  /,  m,  n,  o,  he 
says,  "  Discoides  siibuculus ;  Kamisol-Knopff:  Discum  Germanorum  imitans,  si  versum  vel 
supinum  consideramus,  a  Vertice  rosacea ;  quiuque  seriebus  geminis  capillaceis  et  velut 
acu  pictis;  in  vertice  figuram  rosulag  ferens."  Leske,' in  his  'Additamenta  ad  Kleinii 
Echinodermata,'  observes,  in  reference  to  the  figure  given  by  Plott  and  Lister,  "  pro 
Echinite  exhibetur ;  at  vero  quantum  ex  icone  coniicere  licet,  potius  Madreporites  est,  quam 
Echinites.  Nam  striae  capillaceas  ex  centro  progrediunter,  ut  in  Madreporis,  neque  aliqua 
oris  vel  ani  mentio  fit,  prajterea  a  Plotio  Porpites  dicitur,  quod  ipsum  nomen  Madreporis 
petrefactis  tribui  solet.  Tanquam  dubium  corpus,  illud  itaque  omisi."  Of  Lang's  figure 
Leske  says,  "  mea  sententia  firma  manet,  hsec  corpora  non  Echinitas,  sed  jMadreporitas  esse." 

The  figures  of  this  Urchin  given  by  Parkinson  of  English  specimens,  and  by  Brongniart  of 
French,  are  very  poor;  and  those  of  Bronn  and  Goldfuss  of  German  forms,  are  not  satisfactory. 
The  first  real  good  drawing  is  that  given  by  Professor  Desor  in  his  valuable  '  Monograph 
on  the  Galerites,'  and  since  then  Professor  E.  Forbes'  beautiful  plate  of  this  species  in  the 
'Memoirs  of  the  Geological  Survey,'  decade  1,  pi.  vii,  leaves  nothing  to  be  desired; 
subsequently  admirable  figures  have  been  pubUshed  in  the  '  Paleontologie  Francaise, 
Terrain  Cretace,'  and  in  the  Echinides  of  the  department  of  the  Sarthe,  by  M.  Cotteau. 

The  test  is  small,  orbicular,  or  slightly  pentagonal,  the  upper  sm-face  convex,  more  or 
less  conical,  and  divided  into  five  broad  and  five  narrow  segments  by  the  poriferous  zones, 
Avhicli  radiate  with  mathematical  accuracy  from  the  circumference  of  the  apical  disc,  which 
is  small  and  prominent  at  the  vertex.  The  imder  surface  is  rounded  in  young  and 
concave  in  adult  specimens,  the  small,  circular  mouth-opening  hes  in  a  deep  central 
depression,  and  between  it  and  the  posterior  margin  is  a  large  oblong  vent. 

The  inter-ambulacral  areas  at  the  ambitus  are  nearly  twice  the  width  of  the  ambulacral ; 
the  dorsal  surface  of  large  specimens  contains  thii'teen  plates  in  each  column  between  the 
apical  disc  and  the  basal  angle ;  the  length  of  the  plate  varies  from  the  ambitus,  where 

1  '  Historia  Auimalium  Angliae,'  16/8,  tab.  vii,  fig.  20,  p.  220. 

2  'Historia  Lapidum  Figuratorum  Helvetise,'  1708,  tab.  36, figs.  1,  2,  p.  126. 
5  'Naturalis  Dispositio  Echiuodermatum,'  1734,  tab.  xiv,  sec.  57,  p.  26. 

*  Ibid.,  Additamenta  ad  Kleiuii,  1778,  p.  172. 


FROM  THE  UPPER  GREENSAND.  203 

they  are  longest,  to  tlie  apex,  where  they  are  shortest,  but  their  vertical  depth  is  nearly 
the  same  throughout ;  their  surface  is  thickly  covered  with  minute  secondary  granules 
placed  in  very  regular  horizontal  rows  (fig.  4y).  Each  plate  exhibits  a  more  or  less 
distinct  sub-central  carination,  so  that  in  many  specimens  the  inter-ambulacral  areas 
appear  to  be  partitioned  by  two  prominent  ridges  on  each  side  of  the  line  of  junction  of  the 
plates.  Along  the  carinated  ridge  each  plate  develops  a  larger  tubercle,  and  these  form  a 
complete  series  from  the  base  to  the  summit  (figs.  4,  a,  h,  d,  (/) :  between  this  and  the 
median  suture  there  are  two  smaller  tubercles  placed  horizontally  (fig.  4^),  and  between 
the  carina  and  the  poriferous  zones  are  two  or  more  similar  tubercles  placed  in 
two  oblique  series  with  reference  to  the  larger  central  tubercles  on  the  line  of  carina- 
tion ;  consequently  the  primary  tubercles  placed  between  the  carinated  ridge  and  the 
median  suture  are  horizontal,  and  those  between  the  ridge  and  the  zones  arranged  in 
obhque  rows  (fig.  4).  At  the  ambitus  the  tubercles  are  more  numerous  and  less  regu- 
larly disposed.  The  basal  plates  resemble  very  much  those  on  the  upper  surface ;  in 
full-grown  specimens  they  are  from  six  to  eight  in  number;  they  are  of  the  same  ver- 
tical depth  as  those  on  the  dorsal  surface,  and  are  ornamented  in  a  like  manner. 

The  ambulacral  areas  are  half  the  width  of  the  inter-ambulacral;  the  plates  are 
numerous  and  narrow,  four  plates  occupying  the  vertical  depth  of  one  inter-ambulacral 
plate  (fig.  4  g) ;  they  are  closely  covered  with  small  granulets,  and  each  plate  supports  a 
small  primary  tubercle.  These  tubercles  are  so  placed  that  they  form  oblique  rows  of  twos 
or  threes,  and  do  not  form  direct  vertical  rows.  The  plates  forming  the  ventral  portion 
of  the  areas  are  rather  larger  than  those  on  the  dorsal  surface  (fig.  4  c). 

The  poriferous  zones  are  straight  and  extremely  narrow ;  the  pores  are  unigeminal, 
and  the  pores  of  each  pair  are  obliquely  placed  (fig.  4  //,  g).  Each  inter-ambulacral 
column  contains  twenty-one  plates,  and  each  ambulacral  column  eighty-four,  and 
there  are  one  pair  of  pores  opposite  each  plate;  it  follows  that  each  zone  contains 
eighty-four  pairs  of  pores  ;  all  the  primary  tubercles  are  raised  on  elevated  bosses  in 
areolar  spaces,  and  they  are  ail  perforated  (figs.  ^f,g,  A)- 

The  apical  disc  is  small,  and  makes  a  slight  prominence  at  the  vertex ;  the  right 
antero-lateral  plate  is  the  largest,  and  supports  a  large  madreporiform  body  (fig.  4  e) ;  the 
single  ovarian  plate  is  imperforate,  as  in  all  its  congeners.  The  ocular  plates  are  very 
small,  and  closely  fitted  in  between  the  ovarials. 

The  mouth  is  circular,  and  occupies  a  deep  depression  in  the  centre  of  the  under 
surface ;  it  is  about  one  fourth  the  diameter  of  the  base ;  the  peristome  is  feebly 
decagonal,  and  the  lobes  are  nearly  equal  (fig.  4  c). 

The  vent  occupies  a  considerable  portion  of  the  basal  region  in  the  single  inter-ambu- 
lacrum, between  the  peristome  and  the  border  ;  it  is  of  a  pyriforni  shape,  having  its  small 
extremity  directed  inwards  towards  the  mouth  with  a  series  of  tubercles  surrounding  it 
(fig.  4  c). 

Like  other  Discoidea,  moulds  of  the  interior  diff'er  materially  from  the  external  shape 


204  DISCOIDEA 

of  the  test  in  exhibiting  ten  notches  around  the  margin,  extending  to  the  mouth  on  the 
ventral  surface,  and  disappearing  at  the  lower  third  of  the  dorsal.  Five  of  these  unite 
near  the  mouth,  and  five  continue  singly  to  it.  The  centre  of  the  prominent  interspaces 
of  the  latter  is  marked  by  a  shallow  depression.  This  groove  corresponds  to  the  line  of 
suture  of  the  ambulacral  plates,  and  its  prominent  sides  to  the  pores.  The  ten  deep 
notches  are  caused  by  as  many  internal  ribs,  which  spring  from  the  inner  sides  of  the 
mouth,  and  run  up  the  wall  under  the  carinated  portion  of  each  series  of  inter-ambulacral 
plates . " — Forbes. 

Affinities  and  Differences. — x\fter  a  careful  comparison  of  B.  subuculus  with  the  four 
following  allied  species,  the  late  Professor  Forbes  remarks  •} — The  first,  Discoidea  minima, 
Agass.,  founded  on  a  single  example  from  the  Chalk-marl  of  France,  appears  to  be  only 
one  of  the  less  conical  forms  of  the  young  of  the  species,  such  as  not  uncommonly  occur 
at  Warminster.  The  second,  D.  fisum,  Merian,  is  said  to  be  exactly  like  B.  minima,  and 
only  distinguishable  from  it  and  B.  siihucuhis  by  having  distinctly  perforate  primary 
tubercles ;  this,  however,  is  a  generic  and  not  a  specific  character.  The  third,  B.  turrita, 
Desor,  is  proportionally  higher  than  B.  subuculus.  The  fourth,  B.  infera,  Desor,  has 
primary  tubercles  only  at  the  base.  I  have  little  doubt,  the  Professor  observes,  that  the 
several  so-called  species  just  enumerated  are  only  slight  varieties,  if  as  much,  of  B.  sub- 
uculus. M.  Cotteau  admits  that  B.  pisum  may  be  the  young  of  B.  subuculus,  but  that  the 
three  others  indicated  by  Professor  Forbes  are  certainly  distinct.  B.  subuculus  differs 
from  B.  Bixoni,Yox\i.,m  having  smaller  mouth-  and  vent-openings,  so  that  the  appearance 
of  the  base  is  materially  different. 

Locality  and  Sfratit/raphical  Position. — This  Urchin  is  abundant  in  the  Upper  Green- 
sand  of  Warminster,  and  Chute  Farm,  Wilts ;  in  the  junction  beds  of  Greensand  and 
Chalk-marl  at  ]\Iaiden  Bradley,  Wilts ;  the  Lower  Chalk  at  Weymouth,  and  the  Grey 
Chalk  near  Folkestone.  This  species  is  very  abundant  in  the  different  type  localities  of 
the  Etage  Cenomanien  in  France,  see  p.  189. 

B. — Species  from  the  Lower  Chalk. 
Discoidea  cylindrica,  Lamarck's  sp.     PI.  XLVI,  figs.  1,2;  PI.  XLVII,  figs.  1 — 3. 

Galeeites  cylindricus,  Lamarck.     Aniniaux    sans    Vertebres,  torn,    iii, 

p.  23,  1816. 
—  —  Beslongchamps.     Encycl.    Method.,   Zoophytes, 

t.  ii,  p.  433,  182-1. 
CoNCLUS  Haavkixsii,  Mantell.     Geol.    Trans.,  new    series,    vol.   iii, 

parti,  p.  208,  1828. 
Galeeites  canalicdlatus,  Goldfuss.     Petrefacta  GermauiEe,  vol.  i,  p.  128, 

pi.  xli,  1829. 

'  '  Memoirs  of  the  Geological  Survey,'  Decade  1,  pi.  vii,  p.  4. 


FROM  THE  LOWER  CHALK. 


203 


scutella  depressa, 

hemispherica, 

discoidea  canaliculata, 

Galerites  Hawkinsii, 

discoidea  cylindeica, 

Galerites  cylindkicus, 

DiSCOIDEA  CYLINDRICA, 


HEMISPHERICA, 
CYLINDRICA, 


Woodward.     Geology   of  Norfolk,  p.  52,  pi.  v, 

%.  4,  1833. 
Woodward.     Idem,  pi.  v,  fig.  5,  1833. 
Agassis.     Prodrome,  Mem.  Sc.  Nat.  Neuchatel, 

t.  i,  p.  186,  1836. 
Besmoulins.     Etudes  sur  les  Ecbiiiides,  p.  254, 

1837. 
Agassiz.      Echinid.  foss.   de  la  Suisse,  Part   I, 

p.  92,  pi.  vi,  figs.  13—15,  1839. 
Bujardin.     Animaux  sans  Vertebres  2e  ed.,  t. 

iii,  p.  311,  1840. 
Besor.     Monogr.iphie  des  Galerites,  pi.  viii,  figs. 

8—16,  p.  58,  1840. 
Morris.  Catalogue  of  British  Fossils,  p.  52,  1843. 
Morris.     Idem. 
Agassiz  et   Desor.      Catal.   rais.    les   Ecb.   An 

Sc.  Nat.  3e  ser.,  t.  vii,  p.  147.  1847. 

—  —  Bronn.     Index  Palseontologicus,  p.  429,  1848. 
Galerites  (discoidea)  cylindricus,  Forbes.     Mem.  of  Geol.  Surv.,  Decade  1,  pi.  viii, 

1849. 
d'Orhigmj.   Prod,  de  Pal.  strat.,  t.  ii,  p.  178, 1850. 
Quenstedt.     Hand,  der  Petrefact.,  pi.  xl,  fig.  20, 

p.  583,  1852. 
Gras.    Catal.  Ours.  foss.  de  I'lsere,  p.  43,  1852. 

—  —  Morris.     Catal.  Brit.  Foss.,  2  ed.,  p.  77,  1854. 

—  —  Pictel.     Traite   de  Paleont.,  t.  iv,  p.    228,  pi. 

xcv,  figs.  9—12,  1857. 

—  —  Besor.     Synopsis  des  fichinides  Fossiles,  p.  177, 

pi.  xxix,  fig.  12,  1857. 

—  —  Cotteau.     Paleont.  Fran^aise,  Ter.  Cret.,  t.  vii, 

p.  28,  pi.  1010  et  1011,  18(36. 

—  —  BeLoriol.  Ours,  de  la  Suisse,  pi.  xiii,  fig.  14, 1873. 

Biapiosis. — Test  large,  sub-circular,  slightly  pentagonal ;  upper  surface  hemispherical, 
more  or  less  elevated,  regularly  convex  above,  rounded  vertically  on  the  sides,  and  acutely 
angular  at  the  border ;  base  nearly  flat,  marked  by  impressions  which  correspond  to  the 
internal  carina ;  ambulacra  one  third  the  width  of  inter-ambulacra ;  mouth-opening 
central,  decagonal ;  vent  small,  oblong,  basal,  midway  between  the  peristome  and  border. 

Dimensions. — a.  Height,  one  inch  and  four  tenths ;  latitude,  two  inches  and  one  tenth, 

B.   Height,  one  inch  and  eight  tenths  ;  latitude,  two  inches  and  two  tenths. 

Description. — Whether  this'  common  Chalk  Urchin  was  known  to  Leske  or  not  is 
difficult  to  decide.  My  friend  Professor  Desor  considers  the  notice  on  Echinus  quater- 
fasciatus  to  refer  to  this  species ;  but  a  careful  examination  of  Leske's  figures  leads  me  to 
the  conclusion  that  the  mouth  figured  by  that  author  in  his  PI.  xlvii  represents  some 
■species  of  the  genus  Echinoconus  rather  than  a  Discoidea,  for  they  show  no  trace  of 


discoidea  cylindrica, 
Galerites  cylindricus, 

Discoidea  cylindrica, 


206  DISCOIDEA 

impressions  made  bj'  the  internal  ribs,  so  characteristic  of  the  latter  genus.     For  this 
reason  I  am  of  opinion  that  the  history  of  this  Urcliin  commences  with  Lamarck's  description. 

The  outline  of  Discoidea  ci/K7idrica  is  orbicular,  the  base  is  very  flat,  and  the  upper 
surface  convex,  more  or  less  elevated,  the  amount  varying  with  its  phases  of  growth  from 
a  regularly  hemispherical  form  in  young  shells,  as  in  the  specimen  figured  in  PI.  XLVI, 
fig.  2  a,  to  hemispherico-cylindrical,  its  adult  condition,  as  shown  in  PI.  XLVI,  fig.  1  c, 
and  PI.  XLVII,  fig.  1  a,  h. 

The  inter-ambulacral  areas  are  three  times  the  width  of  the  ambulacral  (fig.  1  a,  h,d); 
the  plates  on  the  sides  and  lower  part  of  the  dorsal  surface  are  broad  horizontally  and 
narrow  vertically  (fig.  1  f/),  and  those  around  the  vertex  are  nearly  square  (fig.  1  e) ; 
near  the  middle  of  each  plate  there  is  a  slight  elevation  of  the  surface  which,  in  connection 
with  others  in  the  column  of  plates,  form  a  line  of  carination,  which  extends  from  the 
apical  disc  to  the  circumference,  and  imparts  a  marked  feature  to  some  old  tests  (PI. 
XLVII,  fig.  1).  On  this  ridge  a  tubercle  rather  larger  than  the  others  is  developed 
(fig.  1  d)  on  the  lower  half  of  each  plate ;  (this  tubercle  with  the  line  of  carination  is  indi- 
cated in  fig.  1  dhy  the  vertical  shading).  On  the  surface  of  each  plate  from  the  sides  of 
the  test  there  are  from  six  to  seven  larger,  and  the  same  number  of  smaller  tubercles 
(fig.  1  d),  all  of  which  are  perforated  and  striated,  and  their  areolar  spaces  surrounded 
by  circles  of  minute  granules  (fig.  2d);  the  quadrate  plates  in  the  upper  portion  of  the 
columns  support  only  the  one  tubercle  growing  on  the  line  of  carinations  already  referred 
to  (fig.  1  e).  In  addition  to  the  perforated  and  striated  tubercles,  the  plates  are  covered 
with  microscopic  granules,  distributed  very  regularly  over  the  surface.  The  series  of 
plates  around  the  angular  border  are  narrow,  and  bear  five  or  six  large  tubercles 
arranged  in  regular  horizontal  rows,  having  areolar  excavations  aroimd  their  base.  Those 
on  the  basal  plates  are  still  more  conspicuously  ornamented  with  rows  of  primary  tuber- 
cles, each  surrounded  by  a  depressed  areola  bounded  ])y  granules,  which  are  larger  and 
more  thickly  set  than  on  the  upper  surface.  The  plates  round  the  mouth  are  smaller  and 
have  fewer  tubercles  (fig.  1  b).  The  inferior  inter-ambulacral  plates  bulge  out  on  each 
half  near  the  margin,  a  prominence  which  is  continuous  with  the  lines  of  carination  above, 
and  indicates  the  position  of  the  internal  ribs  in  the  interior  of  the  test.  PI.  XLVII, 
fig.  2  a,  b,  shows  the  position  of  impressions  made  by  the  internal  ribs  on  a  well-marked 
mould ;  from  this  we  learn  that  the  two  impressions  at  the  base  of  each  inter-ambulacra, 
and  the  ridge  at  the  circumference,  are  due  in  part  to  the  internal  ribs  of  the  test. 

The  ambulacral  areas  are  narrow  and  lanceolate  above,  and  of  the  same  width  and 
more  prominent  at  the  base ;  they  are  composed  of  small  unequal  plates,  of  which  about 
three  correspond  vertically  to  one  inter-ambulacral  plate.  They  are,  however,  very 
irregular  in  size  and  shape,  some  being  narrow,  others  rhomboidal  or  triangular,  with 
small  wedge-shaped  pieces  fitted  into  the  poriferous  zones,  the  whole  forming  a  kind  of 
mosaic  of  many-sized  pieces.  The  plates  at  the  base  and  on  the  upper  surface  are  more 
regular  in  form  and  smaller  in  size  than  those  on  the  sides  (fig.  Id);  each  plate  carries 


FROM  THE  LOWER  CHALK.  207 

one  or  two  small  primary  tubercles ;  at  every  thiixl  plate  one  of  these  is  near  the  zonal 
side  (fig.  2/),  so  that  in  each  ambulacra  there  are  two  marginal  rows  of  small  perforated 
and  crenulated  tubercles  surrounded  by  several  microscopic  granules. 

The  poriferous  zones  are  very  narrow,  and  liave  one  pair  of  small  round  holes  opposite 
each  ambulacral  plate,  which  are  larger  and  more  conspicuous  on  the  dorsal  than  on 
the  ventral  surface ;  on  the  lateral  and  dorsal  surfaces  the  pores  are  unigeminal,  but  at 
the  base,  from  the  narrowness  of  the  plates,  they  fall  into  doable  file  (fig.  2/),  and  near  the 
mouth-opening  two  rows  go  to  each  plate,  the  numl)er  of  pairs  of  pores  corresponding 
with  the  number  of  the  ambulacral  plates ;  taking  the  average  as  equal  to  seven  ambulacral 
plates  for  two  inter-ambulacral  an  average-sized  adult  test  would  have  seventy  pairs  of 
pores  in  the  lateral  and  dorsal  portions  of  the  zones ;  the  exact  number  at  the  base  it  would 
be  difficult  to  estimate,  from  the  narrowness  of  the  plates  and  the  bigeminal  arrangement 
of  the  pores. 

The  base  is  flat  and  the  mouth-opening  occupies  the  centre  of  the  disc ;  it  is  a  small 
obscurely  decagonal  opening  (PL  XL VI,  figs.  1  5,  2  b),  equal  in  diameter  to  one  fourth  the 
distance  between  it  and  the  border ;  the  peristome  is  subcircular  and  divided  into  ten 
equal  lobes  ;  it  is  only  in  some  rare  specimens  that  this  part  of  the  anatomy  of  the  test  is 
shown,  as  the  oral  opening  is  nearly  always  filled  with  closely  adhering  matrix.  Li 
some  fine  specimens  from  the  soft  Grey  Chalk  I  have  been  able  to  clear  out  the  peristome 
and  demonstrate  the  oral  lobes. 

The  vent  is  proportionately  very  small,  oblong,  and  acute  at  each  extremity.  It 
occupies  rather  more  than  one  fourth  of  the  space  between  the  mouth  and  border, 
and  is  distant  from  the  margin  about  its  own  long  diameter  (fig.  li^).  The  plates  of  the 
single  inter-ambulacrum  appear  sharply  incised  by  the  vent,  the  margins  of  which  are  on 
a  level  with  them  except  at  the  inner  extremity,  where  there  is  a  bulging  of  the  plates 
extending  to  the  peristome  (PL  XLVII,  fig.  \b). 

The  apical  disc  is  well  shown  in  my  type-specimen ;  and  this  structure  is  accurately 
drawn  in  PL  XLVI,  fig.  2  c.  It  is  often  prominent  in  consequence  of  the  convexity  of 
its  elements ;  the  five  ovarial  plates  are  of  an  irregular  rhomboidal  figure  and  closely  united 
together ;  four  of  the  five  plates  are  perforated  for  the  passage  of  the  genital  tubes,  the 
single  plate  is  imperforate,  and  the  microscopic  madreporiform  body  occupies  the  entire 
surface  of  the  right  antero-lateral  plate.  The  five  ocular  plates,  each  having  an  orbit, 
are  small  cordate  bodies  wedged  into  the  angles  of  the  ovarials,  fig.  2  c  shows  this 
structure  magnified  six  diameters.  Mr.  Bones'  very  accurate  drawing  renders  any 
lengthened  description  of  the  discal  elements  unnecessary. 

In  PL  XLVII,  fig.  2  a,  b,l  have  figured  a  very  perfect  mould  of  this  Urchin  to  assist 
the  geologist  to  identify  the  species  when  all  the  test  is  absent.  This  mould  is  marked  by 
ten  impressions  made  by  the  internal  carinse  of  the  test,  which  deeply  groove  the  border 
and  base  and  extend  from  the  lower  part  of  the  sides,  pass  along  the  floor  of  the  test  and 
vanish   at   the  peristome.      In   addition   to   these   well-marked    depressions  Professor 


20S  DISCOIDEA 

Desor  describes  and  figures  three  fine  marginal  incisions  nsible  below  and  in  profile  in 
each  cohimn  of  plates,  and  which  assume  a  different  form  in  the  single  inter-ambulacrum 
where  they  are  only  two  in  each  column ;  they  are  here  wider  and  deeper  than  those  in 
the  pairs  of  the  inter-ambulacra. 

PI.  XLVII,  fig.  3,  is  the  drawing  of  the  base  of  a  mould  of  a  monstrosity  of  this 
species,  in  which  there  are  only  four  ambulacra  seen  from  below. 

Affinities  and  Differences. — Blscoidea  cylindrica  cannot  be  mistaken  for  any  of  its 
congeners,  as  it  is  readily  identified  by  its  great  height,  its  inflated  and  sub-cylindrical 
form,  its  perfectly  flat  base,  and  by  the  proportionate  smallness  of  the  oral  opening  and 
the  vent.  Biscoidea  Favrina  is  the  nearest  allied  form ;  this,  however,  differs  from 
D.  cylindrica  in  having  a  larger  vent  placed  nearer  the  border,  and  in  having  the  iuter- 
ambulacral  plates  much  larger ;  each  plate,  in  vertical  height,  corresponding  to  six 
ambulacral  plates. 

Local  if  1/  and  Siratigrapldcal  Position. — This  species  occurs  in  the  Upper  Chalk  of 
Norwich  and  Holt  (Mr.  S.  Woodward,  Sen-),  Chalk  Marl  and  Lower  Chalk  at  Hamsey, 
near  Guildford,  Markham  Gayton,  Charing,  Lewes,  Dover,  Burham,  near  Maidstone, 
Speeton,  Yorkshire ;  the  Chloritic  Marl,  near  Chardstock,  and  in  the  Red  Chalk,  in  the 
highest  of  the  tinted  bands  at  Speeton  CliS",  Yorkshire,  at  the  part  where  the  pink  and 
white  sems  alternate  (Rev.  T.  Wiltshire). 

Foreign  Distribution. — In  France,  in  the  '  Etage  Cenomanien,'  according  to  M. 
Cotteau,  Rouen  (Seine-Inferieure) ;  Pourrain,  Saint-Sauveur  (Yonne) ;  La  Fauge  pres  le 
Villard-de-Lans  (Isere) ;  Saint-Aignan  en  Vercors  (Drome) ;  Castellanne  (Basses-Alpes). 
Lr  Germany,  in  the  Lower  Planer  (stage  with  Ammonites  BJiotomagensis)  =  Chalk-marl 
of  English  authors ;  at  Langelsheim  near  Brunswick  (Strombeck)  ;  at  Rethen,  near  Hilde- 
sheim  (Romer),  near  Paderborn  (Goldfuss),  from  the  Gault  of  the  Mountain  of  Fis, 
according  to  Desor,  and  from  the  Etage  Albien,  Cheville,  Alpes  Vaudoises  =  Lower 
Chalk  (Renevier). 

DiscoiDEA  MINIMA,  Agassiz,  1840.     PI.  XLVII,  fig.  4  a — h. 

DiscoiDEA  MINIMA,  Agassiz.     Catal.  S3'st.  Ectyp.  Foss.,  p.  7,  1840. 

—  —  Desor.     Monogr.  des  Galerites,  p.  56,  pi.  viii,  figs.  1 — 4,  1842. 

—  —  Morris.     Catalogue  of^Britisli  Fossils,  p.  52,  1843. 

—  —  Agassi:  and  Desor.     Catal.  raisonne  des  llchinides,  1847. 

—  —  Morris.     Catalogue  of  British  Fossils,  p.  77,  2nd  ed.,  1854. 

—  —  McCoy.     Contributions  to  British  Palaeontology,  p.  67,  1854. 
_  _  Cotteau.     Paleontol.  Fran9aise,  t.  vii,  pi.  1012,  figs.  1—7,  186G. 

Diagnosis. —  Test  small,  sub-circular ;  height  and  length  equal ;  upper  surface 
inflated ;  base  slightly  convex ;  border  round ;  ambulacra  half  the  width  of  the  inter- 
ambulacra;  tubercles  form  regular  series  on  the  sides  of  the  areas;  mouth  and  vent 
moderately  wide. 


FROM  THE  UPPER  GREENSAND.  209 

Description. — The  specimens  of  this  Urchin  sent  to  me  for  drawing  and  description 
were  so  imperfect  that  I  requested  Mr.  Bone  to  make  accurate  copies  of  the  very  capital 
figures  of  this  species  given  by  my  friend  M.  Cotteau  in  the  '  Paleontologie  Fran9aise,* 
pi.  1012,  figs.  1—7. 

The  test  is  small  and  sub-circular ;  the  upper  surface  inflated  and  convex ;  the 
base  slightly  swollen  in  the  middle,  and  round  at  the  border. 

The  ambulacra  half  the  width  of  the  inter-ambulacra,  with  two  rows  of  primary 
tubercles  extending  from  the  disc  to  the  peristome  (fig.  4  r/,  h) ;  the  plates  supporting, 
besides,  numerous  fine  granules,  which  are  disposed  around  the  base  of  the  tubercles. 
The  poriferous  zones  are  narrow,  the  pores  round,  unigeminal,  slightly  oblique,  and  well 
spaced  out  from  each  other  (fig.  4/ and  fig.  4  ff). 

The  inter-ambulacra  are  formed  of  large  plates ;  at  the  ambitus  each  plate  carries 
three  tubercles,  two  of  which  are  more  conspicuous  and  persistent  than  the  others,  and 
reach  higher  up  the  sides.  The  central  tubercles  extend  from  the  disc  to  the  peristome, 
and  the  zonal  series  is  absent  above  and  below ;  the  larger  tubercles  grow  on  two  slightly 
elevated  longitudinal  carinal  lines  (fig.  4/),  indicated  by  the  direction  of  the  shading  in 
the  figures.  The  granulations  on  the  plates  are  very  fine  and  form  horizontal  beaded 
chains  of  great  delicacy ;  the  primary  tubercles  at  their  base  have  circular  depressed 
areolas  without  encircling  granulations. 

The  small  mouth-opening  has  a  circular  or  sub-decagonal  peristome  and  opens  in  the 
centre  of  the  base,  which  is  shghtly  convex  (fig.  4  a). 

The  vent  is  oval,  and  acuminated  at  the  inner  extremity ;  it  occupies  nearly  two 
thirds  of  the  space  between  the  peristome  and  posterior  border ;  the  aperture  was  closed 
by  a  series  of  ten  anal  plates,  unequal  in  size  (fig.  4  h)  and  covered  with  small  granules  ; 
the  periprocte  at  the  inner  border  is  surrounded  by  seven  small  plates  let  into  a  space 
around  the  vent  like  a  piece  of  mosaic. 

The  apical  disc  is  small  and  composed  of  five  perforated  ovarial  plates,  the  right 
antero-lateral  being  much  the  largest  and  covered  with  the  madreporiform  body ;  the 
surface  of  the  other  four  is  crowded  with  granules  ;  and  the  small  cordate  oculars  are 
wedged  into  the  angles  formed  by  the  ovarial  plates. 

Jffinities  and  Differences. — The  general  form  and  arrangement  of  the  tubercles  on 
D.  minima  resemble  the  young  condition  of  D.  subucuhts,  of  which  some  authors 
consider  it  a  small  variety.  M.  Cotteau^  has  had  an  opportunity  of  examining  with  care  a 
great  number  of  specimens  collected  from  different  localities,  and  says  that  he  has 
acquired  the  certainty  that  this  species  differs  essentially  from  D.  subuculus,  not  only  in 
its  size,  which  is  constantly  smaller,  but  in  its  greater  height,  more  inflated  sides,  and 
convex  base,  and  by  its  granules,  which  ai'e  more  closely  set  together  and  disposed  in 
more  regular  lines  on  the  plates,  and  always  by  its  apical  disc,  which  is  composed  of  five 
perforated  ovarial  plates. 

1  '  Paleontologie  Fran9ai8e,'  tome  vii,  p.  35. 

27 


210  DISCOIDEA 

Localitij  and  Stratigraj)liical  Position. — This  species  is  extremely  rare;  on  the 
authority  of  Professor  M'Coy  one  only  has  been  found  iu  England  in  the  Upper  Greensand 
of  Cambridge  ;  and  this  type-specimen,  with  its  anal  plates,  is  in  the  Woodwardian 
Museum  of  Cambridge. 

Tlie  Foreif/n  Localities,  according  to  M.  Cotteau,  are  Rouen  (Seine-Inferieure),  Neu- 
■chatel  pres  Boulogne  (Pas-de-Calais) ;  Verronnet  (Eure)  ;  La  Chapelle  Saint-Aubin,  Les 
]\Ienus  pres  la  Loupe  (Sarthe)  ;  environs  de  Villedieu  (Loir-et-Cher),  from  the  Etage 
Turonien,  where  it  is  very  rare. 


DiscoiDEA  Favrina,  Bcsor,  1842,  PI.  XLVIII,  fig.  1  a — g. 

DiscoiDEA  F.vvRiXA,  Besor.     Monogr.  Jes  Galerites,  p.  62,  pi.  vii,  figs.  12 — 16,  1842. 
—  —         Forbes.     Mem.  of  Geol.  Survej-,  Decade  I,  descrip.  pi.  viii,  1849. 

Diaf/noms. — Test  sub-pentagonal ;  upper  surface  elevated,  round,  more  or  less  inflated  ; 
base  flat ;  mouth-opening  small ;  vent  oblong,  midway  between  the  peristome  and  border ; 
inter-ambulacra  wide,  two  prominent  rows  of  primaiy  tubercles ;  ambulacra  narrow ;  five 
plates  opposite  one  inter-ambulacral. 

Dimensions. — Height  seven  tenths  of  an  inch  ;  latitude  one  inch. 

Description. — This  Urchin  was  first  figured  by  my  friend  Professor  Desor  under  the 

name   Discoidea  rot/da;   he   informs  us  that  when  the  plates  were  executed  for   his 

beautiful  memoir  on  the  Galeritida  his  knowledge  of  the  D.  rotula  was  limited  to  moulds 

of  this  species,  or  to  moulds  with  a  fragment  of  the  test  adherent,  but  so  much  effaced 

that  it  was  impossible  to  study  its  intimate  structure.     As  he  had  recognised  among 

the  Urchins  sent  to  M.  Agassiz  by  M.  Alex.  Brongniart  from  the  "  Glauconie"  of  Bouen, 

who  had  first  figured  D.  rotula,  a  species  very  similar  in  form  to  the  others,  he  thought  he 

could  identify  it  with  D.  rotula ;  subsequently  ^L  Favre,  of  Geneva,  sent  from  Saxonnet 

a  specimen  of  D.  rotula  with  its  test  perfectly  preserved.     This  specimen  he  compared 

with  those  sent  from  Rouen,  when  he  found  that  the  tubercles  on  D.  rotula  from  Saxonnet 

were  very  different  from  those  on  the  specimens    from   Rouen,    for  instead  of  being 

scattered  without  apparent  order  on  the  surface  of  the  test,  they  formed  horizontal  series 

very  continuous,  resembling  those  on  D.  macrojiyga.     This  discovery  determined  M. 

Desor  to  separate  the   Saxonnet  specimen  from  those  derived  from  the  "  Glauconie  "  of 

Rouen,  and  to  describe  it  under  the  name  Discoidea  Favrina. 

The  specimen  I  have  figured  from  the  British  Musemu  collection  was  identified  by  the 
late  Dr.  Woodward  as  the  representative  of  Desor's  species  from  the  Upper  Greensand ; 
the  test  has  a  subpentagonal  outline,  is  considerably  elevated  with  a  convex  dorsal  surface 


FROM  THE  UPPER  GREENSAND.  211 

(fig.  1  c) ;  the  base  is  flat ;  the  mouth-opening  small  (fig.  1  b,  and  the  oblong  vent 
occupies  a  space  midway  between  the  peristome  and  the  border. 

The  arabulacral  areas  are  formed  of  small  irregular-shaped  plates,  many  of  a  triangular 
form.     On  each  of  these  is  a  primary  tubercle,  so  placed  that  on  every  three  plates  we 

observe    an  oblique    disposition  like  this  .  :  *      The  poriferous  zones  are  very  narrow, 

and  there  is  one  pair  of  pores  opposite  each  of  the  arabulacral  plates,  of  which  five  are  packed 
within  the  vertical  depth  of  one  inter-ambulacral.  Fig.  1  e  shows  the  structure  of  one  of 
these  areas  magnified  four  diameters,  and  the  form  of  the  individual  plates  is  well 
delineated  in  this  drawing. 

The  inter-ambulacral  areas  are  four  times  the  width  of  the  arabulacral ;  the  tubercles 
are  arranged  with  much  regularity,  and  two  series  in  each  area,  situated  about  one  third 
the  distance  between  the  zones  and  the  median  sutures,  are  formed  of  larger  primary 
tubercles,  which  are  elevated  on  a  slight  carinal  ridge  of  the  plate,  and  extend  unin- 
terruptedly from  the  apical  disc  to  the  peristome  ;  this  ridge  is  faintly  represented 
by  a  vertical  line  in  fig.  1  e ;  besides  the  longitudinal  series  there  are  several  other 
tubercles  very  regularly  arranged,  and  between  them  the  surface  of  the  plates  is  covered 
with  a  microscopic  granulation.  The  tubercles  are  larger  at  the  base,  and  form  hori- 
zontal rows  on  the  plates  (fig.  1  y),  where  several  of  the  basal  plates  are  drawn  four  dia- 
meters to  show  this  arrangement  of  the  tubercles  with  their  encircling  granules.  The 
structure  of  the  basal  portion  of  the  single  inter-ambulacrum  with  the  oblong  vent  is  w^ell 
shown  in  fig.  1/,  where  the  two  primary  series  of  tubercles  flank  the  periprocte,  and  others 
fill  up  the  intermediate  spaces ;  in  this  figure,  likewise  magnified  four  diameters,  we  observe 
that  each  alternate  plate  of  the  basal  portion  of  the  ambulacra  supports  a  priraary  tubercle. 

The  apical  disc  (fig.  1  d)  is  formed  of  five  irregular,  pear-shaped  ovarial  plates,  four  of 
which  are  perforated ;  the  right  antero-lateral  is  larger  than  the  others,  and  supports  as 
usual  the  madreporiform  body.  The  five  heart-shaped  oculars  with  their  microscopic 
orbits  are  wedged  between  the  ovarials  ;  the  elements  of  the  disc  are  well  soldered  together 
and  form  a  compact  body. 

The  mouth-opening  is  small,  and  occupies  a  slight  central  depression  (fig.  1  b). 

Afmities  and  Differences. — This  Urchin  closely  resembles  D.  cylindrica,  a  species 
which  presents  many  interesting  varieties  of  size  and  form  from  difi'erent  localities,  scarcely 
two  specimens  from  the  Grey  Chalk  of  Folkestone,  or  the  Lower  Chalk  of  the  South  of 
England,  being  precisely  alike.  The  same  remark  may  be  made  of  the  specimens  of 
B.  cjjlindrica  now  before  me  from  the  Planer  of  Hanover,  the  Craie  Chlorite  of  La  Fauge 
(Isere),  and  the  £tage  Cenomanien  of  Saint- Aignan  (Drome),  and  of  other  departments  of 
France;  such  being  the  case  I  accept  B.  Favrina  only  as  a  provisional  species 
until  a  series  of  specimens  have  been  found  which  may  determine  more  accurately 
its  specific  charactei's. 

Locality  and  Stratigrapliical  Position. — The  specimen  I  have  figured  belongs  to  the 


212  DISCOIDEA. 

British  Museum,  and  was  obtained  from  the  Upper  Greensand.  Professor  Desor's  type 
was  collected  by  Professor  Favre  from  the  same  stage  at  Saxonnet.  My  late  colleague. 
Professor  Forbes,  stated  in  his  note  on  alUed  British  species  of  D.  cylindrica  .•  "  I  think 
it  not  improbable  that  in  the  end  we  shall  have  to  adopt  the  specific  appellation 
Favrina  for  the  Greensand  species ;  and  that  the  Chalk  specimens  alluded  to  will  prove 
varieties  of  cylindrica;  but  a  comparison  of  the  types  themselves  only  can  settle  the 
matter."  '  Memoirs  of  the  Geological  Survey,  British  Organic  Remains,'  Decade  i ;  note 
to  plate  viii,  Biscoidea  cylindrica. 


DiscoiDEA  DixoNi,  Forbes,  1850.     PI.  XLVIII,  fig.  2  a—d,  fig.  3  a,  b. 

DiscoiDEA  DixoNi,  Forbes,  in  Dixon's  Geology  of  Sussex,  pi.  xxiv,  figs.  13,  14,  1850. 
—  —         Forbes,  in  Morris's  Catal.  of  British  Fossils,  2nd  ed.,  p.  77,  1854. 

Diagnosis. — Test  small,  circular ;  upper  surface  elevated,  dorsum  convex,  sides 
inflated  ;  base  slightly  convex ;  mouth-opening  and  vent  very  small ;  inter-ambulacra 
wide ;  two  rows  of  primary  tubercles  more  prominent  than  the  others ;  surface  of  the 
plates  finely  granulated ;  l)asal  tubercles  larger ;  apical  disc  small ;  the  five  genital  plates 
all  perforated. 

Dimensions. — Height  five  twentieths  of  an  inch  ;  latitude  three  tenths  of  an  inch. 

Description. — In  describing  this  Urchin,  which  he  found  in  Mr.  Frederick  Dixon's 
'  Cretaceous  Fossils  from  Sussex,'  my  late  colleague,  Professor  Edward  Forbes,  observes  : 
"  In  form  and  size  this  species  resembles  Discoidea  subuculus ;  also  in  the  proportional 
number  of  ambulacral  as  compared  with  the  inter-ambulacral  plates,  and  the  granulation 
of  their  surfaces.  It  is  distinguished,  however,  by  the  proportions  and  dimensions  of 
mouth  and  anus  as  compared  with  the  whole  ventral  surface.  The  mouth,  instead  of 
being  (as  in  subucuhis)  nearly  equal  in  diameter  to  the  distances  between  its  sides  and 
the  margin  of  the  inferior  surface,  is  scarcely  half  that  size,  and  the  anus,  instead  of 
occupying  the  greater  part  of  the  space  between  the  mouth  and  the  margin,  fills  less  than 
half  of  it."^ 

This  elegant  little  Urchin  has  likewise  the  upper  surface  elevated,  the  sides  inflated, 
and  the  base  slightly  convex,  a  careful  comparisou  of  type-specimens  discloses  the  affinities 
and  differences  subsisting  between  these  congeneric  forms. 

The  ambulacral  areas,  half  the  width  of  the  inter-ambulacral,  have  a  row  of  small 
tubercles  on  the  zonal  side  of  the  plates,  one  tubercle  on  every  other  plate  in  the  column, 
and  a  second  row  more  irregular  than  the  former,  filHng  in  only  the  wider  part  of  the  area 

'   '  Dixon's  Geology  and  Fossils  of  Sussex,'  p.  341. 


ECHINOCONUS.  213 

■('iig.  2d);  the  surface  of  the  plates  is  likewise  covered  with  numerous  microscopic 
granules  set  in  horizontal  rows.  There  are  four  ambulacral  plates  opposite  each  inter- 
ambulacral,  and  a  pair  of  oblique  pores  correspond  to  each  ambulacral  plate. 

The  inter-ambulacral  areas  have  two  rows  of  primary  tubercles,  nearer  the  zonal  than 
the  sutural  side  of  the  plates  ;  these  rows  extend  from  the  disc  to  the  peristome  (fig.  2  a,  b, 
•  and  fig.  3  a) ;  each  plate  besides,  near  the  ambitus,  supports  four  smaller  tubercles 
'placed  less  regular  on  the  surface  than  those  forming  the  vertical  series.  The  surface  of 
the  plates  is  likewise  covered  with  a  most  abundant  development  of  microscopic  granules 
arranged  in  horizontal  rows  in  the  direction  of  the  long  diameter  of  the  plate.  Fig.  2  d 
shows  this  condition  of  the  surface  in  the  plates  of  both  areas  magnified  six  times ;  all  the 
tubercles  are  perforated  and  crenulated.  Those  on  the  base  are  large  as  shown  in  fig.  3  a, 
where  the  test  is  magnified  twice ;  and  the  details  of  a  portion  of  the  same  are  very  well 
exhibited  in  fig.  3  h,  where  a  portion  of  both  areas  is  accurately  drawn  eight  times  the 
natural  size.  These  admirable  drawings  by  my  friend  Mr.  C.  R.  Bone  render  any 
detailed  description  unnecessary,  as  they  are  correct  representations  of  the  minute  anatomy 
•of  the  test  carefully  drawn  under  a  lens. 

The  apical  disc  is  level  with  the  general  surface,  and  all  the  five  ovarial  plates  are 
perforated  (fig.  2  c),  as  in  D.  minima. 

The  base  is  slightly  convex ;  the  small  mouth-opeuing  is  quite  superficial,  and  its 
.peristome  is  marked  with  microscopic  incisions  ;  the  vent  is  oblong,  and  occupies  the 
middle  of  the  space  between  the  peristome  and  border,  which  is  rounded  and  inflated, 
but  never  angular  as  in  B.  snbuculus. 

Affinities  and  Differences.— ^\\Qn  compared  with  D.  suLucuIas  it  is  distinguished  by 
•the  proportions  and  dimensions  of  mouth  and  vent  as  compared  with  the  whole  ventral  area, 
which  are  much  larger  in  D.  subiicidus  than  in  D.  Dixoni.  M.  Cotteau  is  inclined  to 
unite  D.  Dixoni  to  D.  minima,  as  the  apical  disc  in  both  has  each  of  the  five  genital  plates 
^perforated,  whereas,  in  other  congeneric  forms,  only  fom-  of  the  ovarials  are  so. 

Locality  and  StratiffrapMcal  Position.— The  type-specimen  was  collected  from  the 
White  Chalk  of  Sussex,  and  the  original  of  our  figures  belongs  to  the  British  Museum. 


Gemcs — Echinoconus,  Breynim,  1732. 
CoNULUS,  ffZwi,  1734.     EcHiNiTES,  Xe«^e,  1778.     Gtale rites,  Zamarc/:,  ISO  1  . 

Shell  round,  oval,  or  pentagonal ;  enlarged  a  little  before  and  slightly  contracted 
behind  ;  upper  surface  more  or  less  elevated,  and  having  a  rounded  or  conoidal  form ; 
:summit  central ;  under  surface  flat,  border  rounded  or  angular,  sometimes  concave  in  the 
middle,  rarely  undulated  by  the  depression  of  the  ambulacra. 

Mouth-opening   small,  circular,  decagonal,  in    the  centre  of  the   base;    peristome 


214  ECHINOCONUS 

notched  with  internal  auricles,  and  supporting  a  pentagonal  masticating  apparatus  ;  vent 
oval,  acuminated  above,  opening  on  the  border,  either  marginal  or  infra-marginal. 

Ambulacra  lanceolate ;  poriferous  zones  narrow ;  pores  unigeminal,  except  near  the 
peristome,  Avhere  they  are  trigeminal. 

Inter-ambulacra  wide,  with  numerous  primary  tubercles,  small  on  the  sides  and 
upper  surface,  and  larger  at  the  base ;  in  both  crenulated  and  perforated  ;  miliary  granules 
either  microscopic  and  homogeneous,  filling  up  all  the  intermediate  spaces,  or  larger  and 
more  developed,  and  disposed  in  regular  cii'cles  around  the  primary  tubercles. 

The  apical  disc,  placed  at  the  centre  of  the  summit,  is  quadrangular,  solid,  and 
compact,  and  composed  of  four  perforate  and  one  imperforate  ovarial  plates  ;  the  right 
antero-lateral  is  much  the  largest,  and  is  prolonged  posteriorly  with  a  portion  of  the 
madreporiform  body  into  the  centre  of  the  disc ;  the  three  other  plates  are  much  smaller, 
and  terminate  externally  in  prominent  angles,  in  which  the  genital  aperture  is  pierced. 
The  five  ocular  plates  are  very  small,  and  interposed  between  the  angles  of  the  ovarials. 

The  genus  EcMnoconus  is  distinguished  from  Discoidea  by  the  position  of  the  vent, 
and  the  absence  of  projecting  processes  from  the  interior  of  the  test ;  from  Pygaster  by  its 
infra-marginal  vent,  absence  of  a  dorsal  aperture,  and  its  elevated  conoidal  test ;  from 
Holedjjjms  by  its  elevated  profile  and  much  smaller  mouth-  and  vent-openings ;  from  Fyrina 
in  the  quadrangular  structure  of  the  apical  disc,  its  more  pentagonal  and  conoidal 
form  and  regular  decagonal  peristome  provided  with  five  jaws,  and  by  its  infra-marginal 
vent. 

In  Professor  Desor's  valuable  Monograph  on  the  Galerites  twelve  species  are  beauti- 
fully and  accurately  figured  belonging  to  the  genus  Echinoconus,  such  as  I  have  defined 
it ;  after  a  careful  study  of  this  series,  and  a  comparison  with  a  collection  of  specimens  of 
many  varieties  now  before  me,  I  have  come  to  the  conclusion  that  they  all  are  referable 
to  four  types,  each  of  which  may  be  described  as  a  distinct  species.     These  are — 

1st.  B.  casfanea. — Has  an  oblong  form,  enlarged  anteriorly  and  contracted  posteriorly  ; 
the  upper  surface  depressed ;  it  belongs  to  the  Upper  Greensand,  the  Chalk-marl,  and 
Lower  Chalk. 

2nd.  E.  sub-rotundus. — Has  a  tall,  round,  or  sub-globular  test,  and  appears  to  be  one 
of  the  many  forms  which  were  figured  by  Klein  and  described  by  Leske  under  the  name 
Echinites  vulgaris ;  the  specimens  grouped  together  were  siliceous  moulds,  entirely  destitute 
of  shell,  and  clearly  referable  to  several  specific  forms ;  one  of  them  may  represent  the 
beautifid  test  I  have  figured ;  but  as  it  is  impossible  to  determine  its  identity,  I  pi'efer 
retaining  the  appropriate  name  given  to  it  by  Mantell.  This  species  is  collected  from 
the  Lower  Chalk  of  Sussex,  and  several  of  my  specimens  came  from  Lewes. 

3rd.  E.  conicus. — This  is  the  true  Echinoconus  vere  conicus  ;  marmo-terrestris, 
creta  rejiletus ;  ex  cretcB  fodhik  Ca/itianis,  oi  Breynius  ;  two  years  later  Klein  named  it 
Comdus  albogalerns  on  account  of  its  fancied  resemblance  to  the  white  caps  worn  by  the 
priests  of  Jupiter  ;  it  has  been  frequently  figured  (see  the  synonyms  of  this  species)  and 


FROM  THE    LOWER   CHALK.  215 

■described  under  that  name;  there  never  was  any  mistake  about  the  typical  form  of  this 
species ;  although  its  generic  and  specific  names  have  been  frequently  changed ;  in  justice 
to  its  original  author  I  have  restored  its  old  name.     It  appertains  to  the  Medial  Chalk. 

4th.  E.  abhreviatus. — This  species  was  proposed  by  Lamarck  for  a  large  flint  mould 
figured  by  Leske ;  but  whether  that  form  is  the  prototype  of  the  Urchin  to  which  I  now 
apply  the  name  is  uncertain,  for  moulds  seldom  possess  specific  characters  and  ought 
never  to  have  been  described  and  figured  as  representatives  of  species ;  moulds  having 
been  so  admitted  by  former  authors  have  led  to  interminable  confusion,  and  E.  abhre- 
viatus is  one  of  many  examples  that  might  be  adduced  of  this  error.  My  learned  friend, 
Professor  Desor,  in  his  valuable  Monograph,  has  cited  thirty-one  references  to  Galerites 
abbreviata,  Lamk.,  and  given  excellent  figures  of  one  of  the  varieties,  which  is  the 
G.  vulgaris  of  Goldfuss  and  Bronn.  The  first  figure  that  can  be  relied  upon  as  truly 
representing  E.  abhreviatus,  Desor,  is  that  given  in  Woodward's  '  Geology  of  Norfolk,'  pi.  v, 
figs.  2  and  3,  p.  47,  where  it  is  entered  in  his  stratigraphical  list  of  fossils  as  G.  vulgaris, 
I  have  a  series  of  type-specimens  of  this  Urchin  from  the  same  chalk  pits,  and  have 
ascertained  the  accuracy  of  this  identification  ;  we  next  find  that  G.  vulgaris,  Woodward, 
is  G.  angulosa,  Desor,  pi.  iv,  figs.  5 — 7,  and  Caratomus  liemisph(Bricus,  Desor,  pi.  v, 
figs.  14 — 19  ;  both  these  species  were  drawn  and  described  from  English  specimens  collected 
from  the  White  Chalk  of  Norwich,  and  sent  by  the  Marquis  of  Northampton  to  Professor 
Agassiz,  so  that  there  can  be  no  mistake  about  the  identity  of  the  original  specimens  most 
beautifully  and  accurately  figured  in  Desor's  valuable  work. 

A. — Species  from  the  Lower  Chalk. 

EcHiNocoNUS  CASTANEA,  Brongniart,  1822.     PI.  LI,  fig.  2  a — g,  fig.  3. 

Ntjcleolites  CASTANEA,        Brongniart.      Geol.   Environs  Paris,  pi.  q,  figs.   13,   14, 

1S22. 

—  —  Defrance.     Diet.  Sc.  Nat.,  tome  35,  p.  214,  1825. 
Galerites  castanea,  Agassiz.     Echinod.  Foss.  Suisse,  pi.  xii,  fig.  7 — 9,  p.  77, 

1839. 
Catopygus  CASTANEA,  Agassiz.     Prodrome  des  iScbiniJes,  p.  185,  1835. 

Pykina  CASTANEA,  DesmouHns.     Etudes  Echiiiides,  p.  185,  1837. 

Galerites  Kothomagensis,  Agassiz.     Cat.  Syst.  Ectyp.,  p.  ". 

—  CASTANEA,  Besor.     Monogr.  des  Galerites,  pi.  iv,  figs.  12 — IC,  p.  23, 

1842. 

—  —  Agassiz  and  Besnr.     Catal.  rais.  des  Echinides,  Ann.  Sc. 

Nat.,  3rd  series,  vol.  vii,  p.  149,  1847. 

—  —  Morris.     Catalogue  of  British  Fossils,  p.  SO,  1854. 

—  —  Forbes.     Mem.  Geol.  Surv.,  Decade  iii,  pi.  vii,  1850. 
EcHINOCONUS  CASTANEA,        d'Orbigny.     Revue  deZool.,  p.  21,  1854. 

Galerites  Kothomagensis,  Sismomla.    Echin.  Foss.  de  Nizza  p.  51,  pi.  2,  figs.  8 10, 

1843. 
EcHiNocoNUS  CASTANEA,     Cotteau.     Paleoutol.  Frau^aise,  t.  vi,  p.  503,  pi.  990. 

—  —  Be  Loriol.     Ours,  de  la  Suisse,  pi.  xiv,  fig.  1,  1873. 


216  ECHINOCONUS 

Biapiosis. — Test  oval,  pentagonal,  enlarged  anteriorly,  contracted  and  rounded- 
posteriorly  ;  upper  surface  elevated  and  convex  ;  sides  inflated;  base  contracted,  slightly 
convex  or  flat.  Mouth-opening  small,  roundish,  and  central ;  vent  large,  elliptical, 
marginal ;  ambulacra  narrow,  prominent,  corresponding  to  the  angles  of  the  test. 
Poriferous  zones  linear,  pores  unigeminal ;  apical  disc  small,  central,  soldered  to  the  plates^ 
of  the  test. 

Bimensions. — The  following  measurement  of  six  specimens  is  given  to  show  the- 
variability  of  the  proportions  of  this  species. 


A. 

B. 

c. 

D. 

E. 

F. 

G.  C. 

G.  C. 

G.  C. 

U.  G. 

C.  M. 

C.  M. 

ength 

2 

1    *' 

1^ 

iiV 

1 

9 
10 

readth      . 

lA 

It^o 

ll^ 

1 

9 
10 

9 
10 

eight 

li^ 

1^ 

17 
20 

9 
10 

tV 

6 
10 

G.  c.  means  Gritty  Chalk ;  u.  g.  Upper  Greensand ;  c.  m.  Chloritic  Marl ;  and  the  measurements  are^ 
in  inches  and  parts  of  an  inch. 

Description. — The  two  Urchins,  from  the  cretaceous  rocks  of  Savoy,  drawn  in  pi.  q,. 
figs.  ]4  and  17,  of  M.  Alex.  Bronguiart's  'Description  Geologique  des  Environs  de 
Paris,'  and  described  under  the  names  Nucleolitcs  castaiiea,  Al.  Br.,  fig.  14,  and 
Nucleolifes  depressa,  Al.  Br.,  fig.  17,  have  occasioned  much  diversity  of  opinion  among 
Palaeontologists  in  consequence  of  the  unsatisfactory  condition  of  the  specimens  them- 
selves and  the  inadequacy  of  the  figures  for  subsequent  determination. 

Having  collected  many  specimens  of  this  species  showing  its  various  stages  of  growth, 
I  am  enabled  to  state  that  the  two  forms  figured  by  Brongniart  are  only  different  conditions 
of  the  same  species,  my  larger  shells  agreeing  with  K  castanea  and  the  smaller  with 
N.  depressa. 

I  have  given  the  anatomy  of  the  test  with  ample  details  of  structure  of  the  largest 
specimen  I  have  seen  from  a  very  fine  fossil  in  my  collection  (fig.  2  a— y) ;  the  smaller 
and  commoner  shell  is  drawn  in  fig.  3. 

The  distinctness  of  the  two  forms  has  been  persistently  maintained  by  most  foreign 
authors,  as  our  table  of  synonyms  shows ;  nevertheless  in  this,  as  in  other  matters, 
authority  must  bend  to  facts,  and  dry  anatomy  settle  the  question  of  the  unity  of  the 
species. 

The  British  specimens  of  Eclnnoconus  castanea  nearly  all  belong  to  the  small  variety ; 
these  were  collected  from  the  Chloritic  Marl  near  Chaldon,  Dorset,  and  most  of  them 
have  the  test  beautifully  preserved.  My  larger  specimens  were  obtained  from  the  bed  of 
hard  gritty  siliceous  Chalk  near  Folkestone,  and  are  equally  well  preserved,  so  that  both 
varieties  belong  to  the  lower  portion  of  the  Cretaceous  formation. 

All  my  specimens  are  of  an  ovate  or  sub-globular  form,  incKning  to  a  pentangular  or 


FROM  THE  UPPER   GREENSAND.  217 

hexangular  outline.  They  vary  much  in  the  degree  of  height  and  tumidity,  as  compared 
with  their  length  and  breadth ;  the  upper  surface  is  sometimes  convex  and  sometimes 
depressed  ;  the  anterior  half  of  the  shell  is  more  enlarged  than  the  posterior,  the  widest 
portion  being  the  region  across  the  antero-lateral  ambulacra  (fig.  2  b,  d).  The  obscure 
angles,  when  they  are  five,  correspond  to  the  ambulacral  areas ;  when  there  is  a  sixth  it 
is  in  the  centre  of  the  sinde  inter-ambulacrum.  The  sides  are  so  rounded  that  their 
most  tumid  portions  are  central  or  sub-central. 

In  the  large  specimen  (fig.  2  h)  the  base  is  flat,  inclining  to  concave,  in  the  smaller 
specimens  from  the  Chloritic  Marl,  as  in  fig.  3,  the  border  is  so  rounded  off  at  the  sides 
that  it  becomes  slightly  convex,  in  the  still  smaller  varieties  it  is  mostly  flat. 

The  ambulacral  areas  are  narrow,  tapering  towards  the  disc  and  peristome,  and  widest 
above  the  ambitus  (fig.  2  a,  b,  c) ;  they  are  formed  of  narrow  plates  four  or  five  of  which  are 
opposite  one  inter-ambulacral ;  four  rows  of  tubercles  set  in  a  zig-zag  arrangement  occupy 
the  area  (fig.  2  e),  and  those  at  the  base  are  much  larger  than  those  on  the  sides.  The 
poriferous  zones  are  linear  and  the  very  small  pores  arc  set  in  triple  oblique  pairs, 
six  or  eight  pair  being  opposite  the  vertical  height  of  one  inter-ambulacral  plate. 

The  inter-ambulacral  areas,  four  times  the  width  of  the  ambulacral,  are  formed  of  broad 
and  well-developed  plates  (fig.  2  a,  b,  c)  ;  in  the  large  specimen  (fig.  2  c),  twelve  of  these 
are  found  in  each  column  between  the  disc  and  border,  and  six  between  the  border  and 
peristome ;  each  plate  supports  two  rows  of  tubercles  set  in  irregular  horizontal  lines 
above  each  other,  four  or  five  tubercles  occupying  each  row.  Fig.  2  e  shows  two 
complete  and  two  incomplete  inter-ambulacral  plates,  and  a  portion  of  the  ambulacral 
area  and  poriferous  zones  magnified  four  times  ;  besides  the  primary  tubercles  the  surface 
of  the  plates  of  both  areas  is  covered  with  numerous  microscopic  granules.  The  basal 
have  larger  tubercles  than  the  lateral  plates.  Fig.  2/ shows  two  of  these  plates  from  the 
middle  of  the  base  magnified  four  times ;  the  crenulations  of  the  boss  and  the  perforations 
at  the  summit  are  better  seen  in  this  than  in  the  other  figure. 

The  apical  disc  is  composed  of  five  genital  and  five  ocular  plates  ;  four  of  the  former 
are  perforated  and  the  single  plate  is  imperforate  (fig.  2y).  The  right  antero-lateral 
genital  plate  is  much  the  largest  and  supports  the  madreporiform  body,  which  extends 
backwards  and  fills  the  central  portion  of  the  disc.  The  small  cordate  perforated  oculars 
are  wedged  into  the  angles  formed  by  the  ovarials  and  complete  the  circle  of  the  disc,  the 
elements  of  which  are  well  soldered  together  to  form  a  compact  structure ;  and  the  surface 
of  the  plates  uncovered  by  the  spongy  body  is  studded  with  close-set  microscopic  granules. 

The  mouth-opening  is  small  and  oval  (fig.  2  b),  the  long  diameter  extending  obliquely 
across  the  base  from  the  left  to  the  right  side ;  the  peristome  is  obscurely  decagonal  and 
divided  into  ten  nearly  equal-sized  lobes.  The  base  is  sometimes  flat,  or  slightly  con- 
cave, as  in  the  large  specimen  (fig.  2  b),  or  it  is  flattened  in  the  centre  and  rounded  off  at 
the  sides,  or  sometimes  it  is  slightly  convex  (fig.  3) ;  in  either  case  the  mouth-opening 
is  nearly  in  the  middle. 

28 


21S  ECHINOCONUS 

The  vent  is  elliptical  (fig.  2  d) ;  one  third  larger  than  the  mouth  in  vertical  dimensions  ; 
it  is  placed  at  the  lower  part  of  the  posterior  border  in  the  single  ambulacrum  imme- 
diately below  the  margin  (fig.  2  d),  or  just  within  the  range  of  the  same ;  it  varies  a  little 
in  the  degree  of  its  elevation  in  the  different  specimens  I  have  compared. 

Affinities  and  Differences. — This  species  is  distinguished  from  its  congeners  by  its 
elongated  and  pentagonal  form ;  it  is  enlarged  anteriorly  and  tapers  slightly  posteriorly, 
its  greatest  transverse  diameter  being  across  the  antero-lateral  ambulacra  j  it  becomes 
a  little  narrower  towards  the  posterior  border,  which  is  rounded  with  an  elongated  ridge 
rising  from  the  upper  angle  of  the  elliptical  vent.  The  primary  tubercles  of  both  areas  are 
of  the  same  size ;  they  are  sunk  in  areal  depressions  and  scarcely  rise  above  the  general 
surface  of  the  plates,  the  whole  of  the  intermediate  structure  being  covered  with  numerous 
close-set  granules  ;  so  that  the  shell  of  Echinoconus  castanea  feels  smooth  to  the  touch 
when  compared  with  that  of  Echinoconus  conicus  or  E.  abbreviatus.  In  this  respect  it 
resembles  E.  subrotundus ;  the  latter,  however,  has  a  smoother  test,  with  fewer  and 
smaller  tubercles  on  the  plates ;  besides  this  character  the  elongated  pentagonal  form 
is  very  characteristic  of  E.  castanea. 

Locality  and  Stratit/rapJdcal  Position. — Echinoconus  castanea  is  collected  very  rarely  in 
the  Upper  Greensand.  A  few  specimens  have  been  found  in  this  formation  at  Chute  Farm, 
near  Warminster,  and  one  of  these  now  lies  before  me.  Small  forms  of  this  Urchin  in 
fine  preservation  are  very  characteristic  of  the  Chloritic  Marl  near  Chard,  a  bed  of  Chalk 
Marl  tinged  green  with  scattered  particles  of  silicate  of  iron,  which  lies  between  the  Chalk 
Marl  and  Upper  Greensand,  and  contains  a  most  interesting  suite  of  Echinidce,  all  of 
which  likewise  occur  in  the  Upper  Greensand  formation.  The  large  figured  specimen 
was  obtained  from  the  Chalk  Marl  near  Lewes,  in  Sussex.  I  have  others  that  were 
collected  from  the  bed  of  hard  gritty  Lower  Chalk  near  Folkestone,  a  stratum  which  has 
yielded  many  interesting  Urchins,  as  Salenia  (/ranulosa,  Cijphosohia  simplex,  and  numerous 
Polyzoa.     It  belongs,  therefore,  to  the  lower  division  of  the  Cretaceous  formation. 

Foreign  Distribution. — It  was  collected  by  Mr.  Alex.  Brongniart  in  the  Albien  stage 
of  the  Chalk  at  the  Mountain  of  Fis,  in  Savoy ;  in  the  same  stage  near  Nice,  by  M. 
Cailliand ;  in  France  at  Escragnolles  (Var),  by  MM.  Cotteau  and  Koichlin ;  near  Pres, 
Valley  de  Rencurel,  near  Grenoble  (Isere),  by  M.  Albin  Gras. 


FROM   THE   LOWER   CHxVLK. 


219 


EcHiNOcoNUs  suBROTUNDUs,  MmMl,  1822.     PI.  LII,  fig.  1  a—f;  PI.  LIII,  fig.  2  a—^f. 


fig.  3. 


CoNDLDS  SUBROTUNDUS,      Mantell.     Geol.  of  Susse.x,  p.  191,  tab.   xvii,  figs.   15 — 18, 

1S22. 
Galerites  subrotunda,     Agassiz.     Monogr.  des  Radiaires,  jMem.  Soc.  des  Sc.  Nat.  de 

Neuchatel,  t.  i,  p.  186,  1836. 

—  —  Besmoulins.     fitudes  sur  les  Echinides,  p.  256,  1837. 

—  —  Bvjardin.     In  Lamarck's  Auimaux  sans  Vertebres,  2e  ed., 

t.  iii,  p.  313,  1840. 

—  —  Besor.     Monogr.  des  Galerites,  p.  18,  tab.  ii,  figs.  11 — 14, 

1842. 

—  —  Morris.     Catalogue  of  British  Fossils,  p.  53,  1843. 

—  —  Agassiz  and  Besor.     Catal.  rais.  des  Echinides,  Ann.  Sc. 

Nat.,  3e  serie,  t.  vii,  p.  148,  1847. 

—  Leskei,  Besor.     Id.,  p.  148,  1847. 

—  SUBTRUNCATA,  d'Orhigny.     Prod,  de  Pal.,  t.  ii,  p.  272,  1850. 

—  SUBROTUNDUS,  Forbes.     In  Di.xon's  Geol.  of  Sussex,  p.  340,  1850. 

—  Forbes.     Mem.  of  Geol.  Survey,  decade  iii,  p.  6,  1850. 

—  —  Morris.     Catal.  of  Brit.  Foss.,  2nd  ed.,  p.  80,  1854. 
d'Orbigny.     Rev.  et  Mag.  Zoologie,  t.  vi,  p.  20,  1854. 
Cotteau.      Paleontol.    Francaise    terrains    Cretaces,    t.    vi, 

p.  517,  pi.  997,  figs.  8— 12,  1856. 
Besor.     Synopsis  des  Echinides  Fobs.,  p.  183,  1S5G. 
Cotteau.     Echinides  de  la  Sarthe,  p.  283,  pi.  xlvii,  fig.  4, 

1860. 


ECHINOCONUS        — 


Galebites 
echinoconus 


Diagnosis. — Test  subcircular,  rounded  anteriorly,  a  little  contracted,  and  subangular 
posteriorly ;  upper  surface  elevated,  sub-conoidal  and  convex ;  base  flat,  rounded  at  the 
border,  sides  a  little  inflated ;  mouth-opening  small,  roundish  central ;  vent  large, 
luarginal,  elliptical ;  ambulacra  narrow,  plates  of  both  areas  covered  with  small  flat, 
equal-sized  tubercles. 

Description. — Under  the  name  Galerites  vulgaris,  Leske,  it  is  probable  that  moulds  of 
IE.  subrotundiis  have  been  included.  Klein's  tab.  xiii,  fig.  c — k,  and  tab.  xiv,  fig.  a — k, 
are  cited  by  Lamarck  as  types  of  G.  vulgaris.  As  these  figures  all  represent  siliceous 
moulds,  a  doubt  may  be  allowed  to  rest  on  their  identity  with  the  form  I  have  figured  in 
Plates  LII  and  LIII.  Dr.  Mantell  also  s-ave  the  name  Conulus  subrotmidus  to  a  doubtful 
cast ;  but  Desor  has  published  excellent  figures  of  this  species  from  an  English  specimen 
collected  in  the  Isle  of  Wight,  and  contained  in  the  IMuseum  at  Neufchatel.     Professor 


220  ECHINOCONUS 

Agassiz  made  a  cast  of  this  specimen  for  his  collection  of  moulds  of  fossil  Echinoderms^ 
This  form,  therefore,  has  become  classical,  and  I  prefer  to  retain  it,  Avith  jMantell's  name, 
as  M.  Cotteau  has  done,  in  his  beautiful  work  on  the  '  Fossil  Echinides  of  the  Department 
of  the  Sarthe.' 

Echinoconus  suhrotundus  is  a  common  Urchin  in  the  Lower  Endisli  Chalk.  The 
subcircular  outline  being  rounded  anteriorly,  and  a  little  contracted  posteriorly,  some- 
times is  slightly  sub-pentagonal,  as  in  the  large  specimen  figured  in  PI.  LIII, 
fig.  '2  a,  b ;  the  upper  surface  is  elevated  and  convex,  or  sub-conoidal.  A  fine  series  of 
well-preserved  specimens  gives  about  equal  niunbers  of  both  forms.  The  base  is  narrow 
and  flat,  and  much  rounded  off  at  the  border;  the  sides  are  tall  and  convex,  not  much 
inflated.  Mr.  Bone  has  given  admirable  figures  of  this  species  ia  Pis.  LII  and  LIII,. 
with  full  details  of  the  anatomy  of  the  test. 

The  ambulacral  areas  are  narrow  and  lanceolate,  PI.  LII,  fig.  1  b,  c,  PI.  LIII, 
fig.  2  a,  b,  and  composed  of  small  plates,  of  which  five  are  opposite  one  large  inter- 
ambulacral  plate.  PI.  LIII,  fig.  2  e,  representing  a  portion  of  the  large  test  near  th& 
ambitus  magnified  four  times,  shows  the  structure  of  the  ambulacra ;  two  rows  of  tu- 
bercles occupy  the  area,  and  form  thereon  irregular  oblique  rows ;  the  poriferous  zones  are 
extremely  distinct ;  the  pores  are  very  small,  one  oblique  pair  corresponding  to  each  plate. 

The  inter-ambulacral  areas  are  nearly  three  times  the  width  of  the  ambulacral,  and 
formed  of  wide  deep  plates  (PI.  LII,  fig.  d,  PI.  LIII,  fig.  2  e).  In  the  large  specimen 
(PI.  LIII,  fig.  2  c,  d)  there  are  fifteen  plates  in  each  column  between  the  border  and  the 
disc,  and  six  or  seven  between  the  border  and  tlie  periostome ;  each  plate  supports  three 
or  four  longitudinal  series  of  tubercles  arranged  in  quincuncial  order,  fig.  2  e,  each  sur- 
rounded by  an  ai'eola,  and  having  its  summit  perforated ;  the  tubercles  on  both  areas  are 
very  small,  indistinct,  and  nearly  homogeneous,  and  can  only  be  seen  Avith  a  lens,  so  that 
the  shell  appears  quite  smooth  to  the  naked  eye.  The  inter-tubercular  surface  is  covered 
with  microscopic  granulets. 

The  base  is  flat,  PI.  LII,  fig.  1  a,  PI.  LIII,  fig.  2  b,  sometimes  it  is  undulated  from 
the  convexity  of  the  basal  inter-ambulacra,  and  the  tubercles  are  a  little  larger  than  those 
on  the  sides ;  PI.  LIII,  fig.  3,  represents  the  arrangement  they  assume  on  three  basal 
plates  magnified  six  times ;  the  bosses  are  crenulated,  and  the  tubercles  perforated. 

The  mouth-opening  is  small  and  central,  about  one  sSventli  the  diameter  of  the  base ; 
and  the  periostome  presents  very  feeble  indications  of  entailles  (fig.  2  b). 

The  vent  is  larger  than  the  oral  opening,  and  occupies  the  border  (Pis.  LII  and  LIII) ; 
it  has  an  elliptical  form,  placed  vertically,  the  most  acute  angle  being  directed  upwards 
(PI.  LIII,  fig.  2,  b,  d) ;  the  opening  is  on  the  same  plane  with  the  border  of  the  test,  and  the 
single  inter-ambulacrum  is  neither  tumid  or  rostrated,  like  E.  abbreviatus  (Pi.  LIII,  fig.  1). 

The  apical  disc  is  firmly  soldered  to  the  surrounding  plates,  and  is  almost  always  well 
preserved ;  it  is  small,  and  consists  of  five  ovarial  plates,  four  of  which  are  perforated,  and 
one  single  imperforate,  the  antero-lateral  plate  is  large,  and  projects  into  the  centre  of 


FROM  THE   MEDIAL   CHALK.  221 

the  disc,  supporting  on  its  surface  the  madreporiform  body.  The  five  ocular  plates  are 
very  small  cordate  bodies,  wedged  between  the  ovarials  (PI.  LH,  fig.  e,  PI.  LHI,  2/). 
The  surface  of  all  the  discal  elements  is  covered  with  microscopic  granulets. 

Affinities  and  Differences. — This  species  resembles  some  globular  varieties  of  E. 
vulgaris,  and  is  often  grouped  with  these  in  collections.  It  has  a  more  globular  form 
and  is  less  elongated,  the  ambitus  is  more  rounded,  and  the  vent  opens  higher  up  in  the 
border.  It  differs  from  E.  castanea  in  the  general  outline  of  the  test  by  being  more 
globular,  and  elevated  with  a  more  convex  dorsal  surface.  The  same  characters  dis- 
tinguish this  species  from  E.  conicus,  from  which,  however,  it  further  differs  in  having 
smaller  tubercles,  and  a  more  microscope  form  of  granulation.  It  differs  from  E. 
abbreviatus  in  the  general  form  of  the  test,  and  in  having  much  smoother  plates,  from  the 
smallness  of  its  tubercles ;  those  in  E.  abbreviatus  being  larger,  and  surrounded  by  a 
more  prominent  granulation ;  the  vent  likewise  is  more  inferior,  and  the  single  inter- 
ambulacrum  neither  tumid  nor  rostrated  as  in  this  species. 

Locality  and  Stratip-aphical  Position. — I  collected  my  large  specimen  from  the  Lower 
Chalk,  near  Lewes,  in  Sussex ;  it  is  found  in  the  same  stratum  at  Charing,  in  Kent,  and 
in  the  Lower  or  Hard  Chalk  at  Feltwell  Marborough,  in  Norfolk,  it  is  therefore  a 
fossil  characteristic  of  the  Lower  Chalk,  and  in  this  respect  differs  from  E.  conicus,  E. 
globulus,  and  E.  abbreviatus,  vi\\\d\  all  appertain  to  the  Medial  and  Upper  Chalk.  The  Rev. 
T.  Wiltshire,  E.G.S.,  has  collected  this  species  in  the  Lower  Chalk,  near  Folkestone,  from  a 
stratum  fifteen  feet  above  the  bed  of  hard  gritty  chalk,  but  never  in  the  gritty  chalk  itself. 


B. — Species  from  the  BFedial  Chalk. 


EcHiNOCONUS  CONICUS,  Brcynius,  173.2.     PI.  XLIX,  figs.  2,  3,  4 ;  PI.  L,  figs.  1 — 6. 

Eciiixocoxus  ver£  conicus,  Breynius.     ScbeJ.    de  Echiuis,  p.  57,  pi.    iii,  fig.    12, 

1732. 
CoKHLUs  ALBOGALERCS,  Klein.     Natiir.  dispositio  Echinoderm.,  p.  2-4,  tab.  xiii, 

A,  B,  1734. 
EcHixiTE  CONOIDE,  Bourguet.     Trait.  desPetrif., p.  77, pi.  liii,  fig.  360, 1742. 

CoNULUS  ALBOGALEEXJS,  Leslie.     Apiid  Klein,  p.  1G2,  tab.  xiii,  a,  b,  1778. 

Echinus  —  Gmelin.     Systema  Naturse,  p.  3181,  No.  46,  1789. 

—  —  Bruguiere.     Tab.  Encjcl.  Atlas,  pi.  clii,  figs.  5,  6,  1791. 
CoxuLUs             —  Par/iinso7i.     Organic  Remains,  vol.  iii,  pi.  ii,  figs.  10,  1 1, 

1811. 
Galerites  —  Lamarck.     Animaux  sans  Vert.,  t.  iii,  p.  20,  1816. 

—  —  Befrance.     Die.  Sci.  Nat.,  t.  xviii,  p.  86,  1820. 

—  —  Brongniart.     Foss.  envir.  de  Paris,  p.  631,  pi.  1,  tig.  12, 

1822. 


222 


ECHINOCONUS 


Galerites  pyramidalis, 
conulus  albogaierus, 

Galerites         — 


COXULUS  

Galerites         — 


ECHINONEUS 


DiSCOlDEA  ALBOGjVLEKA, 


Galerites  pyramidalis, 

—  albogalerus, 

—  pyramidalis, 

albogalerus, 

pyramidalis, 

—  albogalerus, 


PYRAMIDALIS, 

ANGULOSA, 

ALBOGALERUS, 


—  PYRAMIDALIS, 
• —  ANGULOSA, 

ALBOGALERUS, 


echinocoxus       — 

pyramidalis, 

angulosus, 

Galerites  albogalerus, 

echixoconus      — 

—  COXICUS, 

—  subpyramidalis, 
Galerites  albogalerus. 


Brongniart.     Idem. 

Mantel! .     Geol.  of  Sussex,  p.  190,  pi.  xvii,  figs.  IG— 19, 

1822. 
Deslongchamps.     Zoophytes  Ecycl.  Method.,  t.  ii,  p.  431, 

1824. 
Goldfuss.     Petrefacta,  t.  i,  p.  127,  pi.  xl,  fig.  19,  182C. 
Fleming.     History  of  British  Animals,  p.  481,  1828. 
Stokes.     Trans.  Geol.  Soc.  Lend.,  2nd  ser.,  vol.  ii,  p.  40G, 

pi.  xlv,  figs.  14,  15,  1829. 
Be  Blainville.     Zoophytes  Die.  So.  Nat.,  t.  Ix,  p.  194, 

1830. 
Agassiz.     Jlonogr.  des  Radiair.,  Mem.  Soc.  Neuf.,  t.  i, 

p.  186,  1836. 
Desmotdins.     Etudes  sur  les  Echinid.,  p.  248,  183". 
Desmoulins.     Idem. 

Agassi:.     Catal.  Syst.  Ectyp.  Foss.,  p.  6,  1839. 
Agassiz.     Idem. 

Diijardin.     In  Lamarck,  2ad  ed.,  t.  iii,  p.  306,  1840.  . 
Dujardin.     In  Lamarck,  idem. 

Bwmer.     Norddeutschen  Kreidegebirges,  p.  32,  1840. 
Desor.     Monogr.  des  Galerites,  tabs,  i  and  xiii,  p.  11, 

1842. 
Desor.     Idem,  p.  13,  tab.  i,  figs.  1  —  3. 
Desor.     Idem,  p.  22,  tab.  iv,  figs.  i> — 7. 
Morris.     Catalogue  of  British  Fossils,  p.  53,  1843. 
Agassis  and  Desor.     Catal.  rais.  des  Echinides,  Ann.  So. 

Nat.,  3rd  ser.,  t.  vii,  p.  148,  1847. 
Agassiz  and  Desor.     Idem. 
Agassiz  and  Desor.     Idem. 
d'Orhlgny.     Pal.  Stratigraph.,  t.  ii,  p.  272,  1850. 
d'Orhigiiy.     Idem. 

Forbes.     In  Dixon's  Geol.  of  Sussex,  p.  340,  1850. 
Sorignet.     Oursin  Foss.  de  I'Eure,  p.  40,  1850. 
Forbes.     Mem.  Geol.  Survey,  decade  iii,  pl.  viii,  1850. 
Bronn.       Letbeea    Geognost.    Kreidegebirges,    p.    191, 

pl.  sxix,  fig.  18,  a,  h,  1857. 
Quenstedt.     Handbuch  der  Petrefalc,  p.  583,  1852. 
d'Orbigny.     Revue  et  Mag.  de  Zoologie,  p.  20,  1854. 
f/'  Orbigny.     Idem. 
d'  Orbigny.     Idem . 
Forbes.     In  Morris's  Catalogue  of  Brit.  Foss.,  2ud  ed., 

p.  SO,  1854. 
Cotteau.     Ech.  Foss.  Pyrenees,  Bulletin  Soc.   Geol.  de 

France,  2e  ser.,  t.  xiii,  p.  258,  1856. 
d'Orbigny.     Palseontol.    Francaise  ter.   Cretaces,  t.  vi, 

p.  513,  pl.  996,  1856. 
d^ Orbigny.     Idem,  pl.  1000,  p.  530. 
Pictet.     Traito  de  Paleont.,  pl.  scv,  fig.  12,  1S57. 


PROM  THE   MEDIAL   CHALK.  223 

Galerites  albogaleeus,        Desor.     Synopsis  des  Echinides  Foss.,  pi.  xxv,  1857. 
EcHiNOCONUs  coxicus,  CotteuH.     Echinides  du  Depart,  de  la  Sarthe,  pi.  47, 

figs.  1—3,  i860. 

Diagnosis. — Test  much  elevated,  conoiclal,  larger  anteriorly  than  posteriorly  ;  slightly 
angular  and  rounded  at  the  border ;  base  flat ;  single  inter-ambulacrum  tumid  and  re- 
curved ;  vent  large,  oval,  infra-marginal ;  mouth-opening  central,  periostoma  decagonal, 
armed  with  five  pairs  of  dentiferous  jaws ;  ambulacra  straight,  narrow,  doubly  lanceolate  ; 
pores  small,  unigeminal,  in  oblique  pairs,  which  become  trigeminal  near  the  periostome  ; 
interambulacra  wide,  angular  ;  tul)ercles  on  both  areas  small,  homogeneous  ;  granules 
abundant,  unequal,  sometimes  elongated  and  prominent ;  apical  disc  small,  quadrangular, 
very  solid. 

Dimensions. — Height,  one  inch  and  five  tenths ;  latitude,  one  inch  and  four  tenths. 

Description. — I  recognise  three  well-marked  vai'ieties  of  form  in  this  Urchin,  which 
have  been  described  as  distinct  species  by  different  systematic  authors  :  these  are, 
according  to  my  reading  of  the  matter,  as  follows  : — 

PoRMA  a.  Cotiica. — This  may  be  regarded  as  the  normal  form,  and  as  such  it  is  figured 

as  the  type  of  the  species. 
EoRMA  /3.  Pijramidalis. — Desor,  '  Monographic  des  Galerites,'  PI.  I,"  figs.    1 — 3  ; 

d'Orbigny,  Paleontologie  PI.  1000,  figs.  5—7.     A  small 

test,  with  pyramidal  elongation  of  the  vertex. 
PoEMA  y.  An(/ulosa. — Desor,  '  Monographic  des   Galerites,'   PI.    4,    figs.    5 — 7,    a 

depressed,  elongated,  and  angular  variety  of  Conica. 

Description. — This  is  the  most  typical  of  all  the  Echinoconi,  and  has  been  well 
figured  and  described  by  most  classical  authors  who  have  described  the  different  forms 
of  this  genus.  It  is  the  true  Echinoconus  vere  conicus  of  Breynius,  1732  ;  two  years  later 
it  was  figured  and  described  as  Conulus  alho-gcderus  by  Klein,  on  account  of  its  supposed 
resemblance  to  the  white  caps  worn  by  the  priests  of  Jupiter.  Lang  figured  it  in  1708 
as  Echiiwmetritis  in  his  '  Historia  Lapidum  figuratorum  Helvetije,'  and  Bourget  in  his 
'  Traitc  de  Petrifactions,'  as  the  EcUnite  conoide,  whilst  Lamarck  made  it  the  type  of  his 
new  genus  Galerites,  reserving  for  it  the  specific  name  idbo-gcderus,  given  by  Klein,  by 
which  it  has  been  known  to  the  present  time. 

The  general  form  of  this  Urchin  is  conical,  varying  in  different  specimens  from  a  tall 
pyramid,  with  very  steep  sides,  to  a  short  one  with  infiated  walls ;  the  base  is  flattened, 
its  circumference  slightly  pentangular,  the  greatest  width  corresponding  to  the  region  of 
the  antero-Iateral  ambulacra  ;  the  basal  angle  is  more  or  less  rounded,  and  the  single 
inter-ambulacnim  tumid  and  recurved. 

The  ambulacral  areas  are  doubly  lanceolate,  and  built  up  of  minute  plates,  which  in 
the  upper  part  of  the  area  are  often  cuneiform  in  shape,  irregular  in  size,  and  some- 


224  ECHINOCONUS 

times  separated  from  each  other  by  small  accessory  pieces ;  near  the  ambitus  they 
have  a  more  regular  shape,  as  seen  in  PI.  L,  fig.  1  d.  All  the  plates  are  narrow,  four  or 
five  corresponding  in  depth  to  one  inter-ambulacral  plate.  In  the  large  specimen  drawn 
in  PI.  XLIX,  fig.  3,  there  are  fifteen  plates  in  each  dorsal  inter-ambulacral  column 
between  the  angle  of  the  disc,  so  that  in  this  specimen,  in  the  same  space,  there  are 
seventy-five  plates  in  each  half  of  an  ambulacral  area ;  there  are  four  rows  of  primary 
tubercles  in  the  widest  part  of  the  area,  which  have  a  zig-zag  arrangement,  the  two 
inner  rows,  which  are  the  most  irregular,  disappear  near  to  the  middle  of  the  base,  and  about 
the  upper  fourth  of  the  dorsal  surface.  The  poriferous  zones  are  very  narrow,  the  pores  uni- 
geminal  and  oblique,  six  pairs  being  often  opposite  one  large  plate  ;  near  the  mouth  they 
form  sets  of  triple  oblique  pairs,  as  in  the  example  (fig.  5),  magnified  four  times;  from 
several  specimens  before  me  in  different  stages  of  weathering,  I  have  ascertained  that  a 
small  cuneiform  plate  is  apportioned  to  each  pair  of  holes ;  this  plate  appears  to  have  been 
formed  of  two  halves,  so  as  to  embrace  the  tubular  feet ;  the  plates,  therefore,  of  the 
poriferous  zones  are  not  perforated  for  the  soft  parts,  but  have,  in  fact,  grown  around 
them  in  the  process  of  development. 

The  inter-ambulacral  areas  are  three  times  the  width  of  the  ambulacral  at  the 
ambitus  (PI.  L,  fig.  1  d) ;  they  are  formed  of  large  plates,  each  supporting  from  10  to  14 
primary  tubercles,  arranged  in  irregular  horizontal  rows,  which  sometimes  assume  an 
hour-glass-shape-like  disposition ;  each  of  these  tubercles  is  spiniferous  (fig.  1/),  and 
is  encircled  by  a  smooth  depressed  areola ;  the  boss  is  large,  mammillated,  and 
crenulated  at  the  summit,  and  the  small  round  head  is  perforated  ;  those  at  the  base  are 
larger,  and  form  more  regular  horizontal  rows  ;  when  examined  with  an  inch  object-glass 
they  present  the  appearance  shown  in  fig.  1/.  The  inter-tubercular  surface  is  covered 
with  rows  of  microscopic  granules  (fig.  1  d,  e,/);  the  tubercles  on  the  upper  surface  all 
supported  short  spines,  which  are  sometimes  seen  i/i  sit//,  those  at  the  base  are  large, 
about  one  fifth  of  an  inch  in  length ;  they  are  slender,  tapering,  smooth,  and  covered  with 
fine  longitudinal  lines,  which  are  delicately  serrated  near  the  summit,  the  stem  is  enlarged 
at  the  base,  where  it  is  encircled  by  a  crenulated  collar  (fig.  3).  Dr.  Bowerbank  made  a 
microscopic  examination  of  the  spines  of  Ecl/inoconi  in  his  collection,  and  found  that  the 
dorsal  spines  of  I^.  conic//s  differed  from  those  of  E.  siibrot//nd//s  in  being  thickened  at 
the  base,  and  set  on  tubercles  as  it  were  sessile,  instead  of  being  shortly  pedunculated,  as 
they  are  in  the  latter  species. 

The  minute  moniliform  spines  of  E.  comcus,  according  to  Dr.  Bowerbank,  arc 
Yja  of  an  inch  in  length,  and  of  equal  diameter  (fig.  4).  Three  were  accurately 
measured,  and  all  were  as  nearly  as  possible  of  the  same  size  and  proportions ;  they  were 
all  perfectly  smooth. 

The  mouth-opening  is  small  and  central  (PI.  L,  fig.  1  d) ;  the  periostome  is  decagonal 
(fig.  5),  and  armed  with  a  dental  lantern  :  this  fact  was  first  discovered  by  INIr.  Charles 
Stokes,  F.G.S.,  and  described  by  him  in  the  'Geological  Transactions;'  since  that  time 


THE 


PALJONTOGRAPHICAL   SOCIETY. 


INSTITUTED  MDCCCXLVII. 


VOLTJME  FOE  1875. 


LONDON 

MDCOCLXXT. 


MONOGRAPH 


on    THE 


BRITISH     FOSSIL 


ECHINODERMATA 


FKOM 


THE   CRETACEOUS  FORMATIONS. 


BY 


THOMAS  WRIGHT,  M.D.,  F.R.S.  Edin.,  F.G.S., 

CORRESPONDING   MEMBER  OF   THE    KOTAi   SOCIETY   OF  SCIENCES  OF  LIEGE,   THE   SOCIETY  OF   NATURAL  SCIENCES    OF 

NEUFCHATEL;    PRESIDENT    OF  THE  GEOLOGICAL  SECTION  OF  THE  BRITISH  ASSOCIATION,  1875  ;   VICE-PRESIDENT 

OF   THE    COTIESWOLD    NATURALISTS'    FIELD     CLUB  ;     CONSULTING     SURGEON    TO   THE     CHELTENHAM 

HOSPITAL;    AND    MEDICAL   OFFICER  OF   HEALTH    FOR   THE  URBAN    SANITARY    DISTRICTS 

OF    CHELTENHAM,    CHARLTON-KINGS,   AND    LECKHAMPTON. 


VOLUME    FIRST. 

PART  SEVENTH. 

ON  THE  ECHINOCONID^,  ECHINONID^,  ECHINOBRISSID^. 
ECHINOLAMPID^,  AND  SPATANGID.^. 

Pases  225—264  ;  Plates  LIII— LXII. 


LONDON: 

PRINTED   FOR  THE    PALJIONTOGRAPHICAL   SOCIETY. 

1875. 


PKINTBD   BY 
J.    E     AULARD,    BAKTHOLOMEW    CLOSE. 


FROM  THE  MEDIAL  CHALK.  225 

other  specimens  exhibiting  the  jaws  have  been  discovered.  The  teeth  are  small,  smooth, 
white,  lanceolate,  triangular,  each  consisting  of  a  concave  lamina,  terminating  below  in 
the  dental  point,  and  strengthened  by  a  prominent  ridge  behind  (fig.  6). 

The  base  is  flat,  and  both  areas  are  covered  with  much  larger  tubercles  than  those 
developed  on  the  dorsal  surface  ;  they  are  arranged  in  irregular  concentric  rows  around  the 
peristome ;  the  single  inter-ambulacrum  is  elongated  posteriorly,  and  more  tumid  towards 
the  border,  which  is  sometimes  rostrated  and  recurved  (PI.  XLIX,  fig.  2  and  fig.  4,  and 
PI.  L,  fig.  1  and  fig.  2).  In  this  portion  the  vent  opens ;  this  aperture  is  one  third 
larger  than  the  mouth,  and  broadly  elliptical  in  a  longitudinal  direction ;  its  margins  are 
thick  and  elevated,  and  appear  to  have  supported  an  anal  membrane.  The  vent  is 
marginal  in  a  majority  of  specimens,  and  is  rarely  seen  above  the  border ;  most  frequently 
it  cuts  that  angle  obliquely  (PI.  L,  figs.  1  and  2). 

The  apical  disc  (PL  L,  fig.  1  e)  is  quadrangular,  and  formed  of  four  perforate 
and  one  small  imperforate  ovarial  plates  ;  the  right  antero- lateral  is  the  largest,  and 
extends  into  the  centre  of  the  disc,  its  surface  supports  the  madreporiform  body ;  the  five 
ocular  plates  are  small  cordate  elements,  closely  wedged  in  the  angle  between  the  ovarials. 

Jffinities  and  Differences. — This  typical  species  difiers  from  its  congeners  in  its  form, 
which  is  always  conical  or  pyramidal ;  the  base  is  flat  and  sub-pentangular,  and  the  single 
inter-ambulacrum  is  posteally  produced,  being  somewhat  tumid  and  recurved.  These 
characters  readily  distinguish  it  from  E.  castanea.  The  straight,  slightly  inclined  sides, 
the  acute  ambital  angle,  and  flat  base,  form  a  good  diagnosis  between  it  and  E.  subrotimdus, 
which  lias  convex  sides,  a  rounded  ambital  border,  narrow  base,  and  small  inter- 
ambulacrum  ;  the  conical  form,  small  tubercles,  and  large  vent  distinguish  it  from 
E.  abbreviatiis. 

LocaUty  and  Sir atigraphical  Position. — This  species  is  found  in  abundance  in  the 
white  Medial  Clialk  of  the  English  Cretaceous  districts.  It  is  very  Common  in  the  south ; 
fine  specimens  are  obtained  at  Gravesend  and  other  localities  in  Kent,  and  at  SwafF- 
ham,  in  Norfolk.  Specimens  showing  the  dentiferous  jaws  are  in  the  collections  of  Mr. 
Stokes,  Dr.  Bowerbank,  and  my  kind  friend  the  Rev.  T.  Wiltshire,  F.G.S. ;  to  whom  I 
am  indebted  for  the  figured  specimen. 

Foreign  Localities. — In  France,  according  to  M.  Cotteau,  it  is  found  in  I'fitage 
Senonien,  at  Meudon,  near  Paris,  near  Sens,  Villeneuve-le-Roi,  and  Charny,  Yonne; 
Beauvais  and  Roquemont,  Oise;  Chartres,  Eure-et-Loire ;  Vernonnet  and  Pinterville, 
Eure ;  Bains-de-Rennes,  Aude ;  the  environs  of  Aix-la-Chapelle,  and  in  the  Island  of 
Ruegen. 


29 


.•  226 


ECHINOCONUS 


EcHiNocoNus  ABBREviATUs,  Desor.     PI.  LII,  fig.  2  a — i  ;  PI.  LIII,  fig.  1. 


—  XODUS, 

—  BULLA, 
ECHIXITES   VULGAKIS, 


Galerites        — 

echinites        

Galerites  truxcatus, 
—        vulgaris, 


CoxuLus  GLOBULUS,  Klein.     Nat.  dispositio  Echinodermatum,  p.  25,  tab.  xiii,  c, 

D,  E,  r,  var.  a,  Wagricus ;  tab.  xiv,  c,  d,  e,  f,  var.  /3, 
Gedanensis,  1734. 

Klein.     Idem.,  tab.  xiv,  g,  h,  Gottlandicus,  1734. 

Klein.     Idem.,  tab.  xiv,  i,  k,  Gedanensis,  1734. 

Leske  (pars),  Klein.  Echin.,  tab.  xiii,  c,  d,  e,  f  ;  tab.  xiv, 
C,  D,  E,  F,  1778. 

Gmelin.     Syst.  Naturae,  p.  3182,  1789. 

Bruguiere.     Encycl.  Method.,  tab.  153,  figs.  6,  7,  1791. 

Lamarck  (pars).     Syst.,  p.  347,  1801. 

Lamarck.     Animaux  sans  Verte'bres,  t.  iii,  p.  20,  1816. 

Schlotheim.     Die  Petrefakten,  p.  320. 

Befrance.     Die.  Sc.  Nat.  Galerites,  t.  viii,  p.  87. 

Beslongchamps.     Encycl.  Method.,  p.  431,  1824. 

—  —  Goldfuss.     Petrefacta  Germania;,  tab.  xl,  fig.  20,  1829. 
_               _  Woodward.     Geology  of  Norfolk,  pi.  v,  fig.  2,  3,1833. 

—  —  Blainville.     Manuel  d'Actinologie,  p.  222,  1834. 

—  PYRAMiDALis,  Besmouliyis  (pars).      Etudes  sur  les  Echinides,  p.  248,  1837. 

—  ABBREViATA,   Besor.     Monographie  des  Galerites,  tab.  iii,  figs.  9 — 17,  p.  20, 

(lion  Lamarck),  1816. 

—  —  Agassiz  and  Besor.     Catal.  raison.,  p.  90  (modeles  s.  65, 

s.  70). 

—  VULGARIS,        d'Orbignij.     Prod.,  t.  ii,  p.  272,  1847. 

—  ABBREVIATUS,  Forbes  (pars).     Mem.  Geol.  Soc.  Survey,  decade  iii,  pi.  viii, 

fig.  5,  1850. 

—  —  Bronn.     Lethea  Geognost.  Kreid.,  p.   192,  pi.  xix,  fig.  17, 

1854. 

—  —  Besor.     Synopsis  des  Echinides  Foss.,  p.  184,  1858. 
_                 _  Morris.     Catal.  of  British  Fossils,  2  ed.,  p.  80,  1854. 

—  —  d'Orbigny.     Revue  de  Zoologie,  p.  20,  1S54. 
EcHiNocoNCS  GLOBULUS,  d'Orbigny.      Pale'ontol.  Franfaise,  t.  vi,  tab.  999,  p.  522, 

1855. 


Diagnosis — Test  thick,  elevated,  conoidal  or  globular,  margin  almost  circular,  not 
angular ;  wider  near  the  anterior  third ;  base  flat,  rounded  at  the  circumference  ;  single 
inter-arabulacrirai  narrow,  tumid,  and  recurved  at  the  border ;  vent  prominent,  infra- 
marginal;  primary  tubercles  surrounded  by  deeply  concave  areolas  ;  mihary  granules 
large  and  thickly  set  on  the  inter-tubercular  spaces. 

Dimensions. — Height,  one  inch  and  one  tenth ;  length,  one  inch  and  four  tenths ; 
latitude,  one  inch  and  three  tenths. 

Descrij)tion. — The  attempt  to  make  out  the  history  of  this  Urchin  has  proved  a  per- 
plexing and  unsatisfactory  task,  inasmuch  as  the  type-specimens  figured  by  Klein  were 


FROM  THE   UPPER  CHALK.  227 

siliceous  moulds  without  any  portion  of  test  attached  thereto,  and  of  these  he  made  three 
species,  Conulus  globulus,  C.  nodus,  and  C.  Bulla.  His  learned  commentator,  Leske,  in 
his  'Additaraenta  ad  Kleinii  Dispositionem  Echinodermatura,'  p.  165,  groups  them  all 
into  one  species,  which  he  described  under  the  name  EcJdnifes  vulgaris,  and  remarks, 
"  Interim  hae  differentiae  si  hasc  corpora  petrefacta,  quae  plerum.que  nuclei  tantum 
Ecldnitaruni  sunt,  attente  contemplor,  mihi  magis  videntur  a  mutatione,  cum  in  petram 
converterentur  Echini  natarales,  pendere,  quam  veram  diversitatem  specierum  indicare. 
Itaqne  etiam  Nodum  et  Bullam  Klenii,  §  53,  54,  ad  varietates  refero.  Prout  enim  testa 
vel  plus  vel  minus  comprimeretur,  eo  vel  obtusa,  vel  conica  magis  nascebatur  figura.  In 
nndtis  speciminibus  vertice  obtnso,  hie  vi  externa  quasi  impressus  videtur."  Lamarck, 
in  his  '  Systeme,'  1801,  and  in  '  Animaux  sans  Vertebres,' 1816,  followed  Leske,  and 
cites  the  Tabs.  XIII  and  XIV  of  Klein's  work  as  types  of  E.  vulgaris. 

Leske,  in  his  '  Additaraenta,'  p.  166,  describes  another  large  mould,  which  he  regards 
as  a  variety  of  Echinites  vulgaris,  and  figures  the  same.  In  Tab.  XL,  figs.  2  and  3,  of 
this  specimen  he  observes,  "  Singularis  et  notatu  digna  varietas,  tarn  propter  brunum 
colorera  ;  quam  propter  insignem  magnitudineni  est  ea,  Tub.  XL,  Van  Phelsum  banc 
iconem  interrogando  cum  Klenii  Tab.  XIII,  g,  h,  comparat.  Singulares  etiam  rugae  et 
lineas  eminentes  in  areis  conspiciuntur.  Ambulacra  singula  biporosa  fuisse  videntur ; 
OS  parvum  ;  anus  oblongus  ;  ambitus  testae  est  circularis.'' 

Lamarck,  in  his  '  Aniniaux  sans  Vertebres,'  tom.  iii,  p.  20,  describes  this  mould  as  a 
new  species  under  the  name  Galerites  abbreviatus,  and  cites  Leske's  figure  as  its  type,  but 
we  are  left  in  ignorance  of  its  true  specific  characters,  as  the  test  is  entirely  wanting. 

Schlotheim,  Deslongcharaps,  Goldfuss,  d'Blaiuville,  Desmoulins,  and  Milne-Edwards, 
in  their  several  works,  have  followed  Lamarck. 

Professor  Desor,  in  his  '  Monographic  des  Galerites,'  first  gave  capital  figures  in 
Tab.  Ill,  fig.  9 — 17,  and  a  concise  description  of  a  large  Urchin  with  the  test  entire, 
and  interior  moulds  of  the  same  from  the  collection  of  M.  de  Luc.  The  specimens  were 
collected  from  the  detritic  sands  of  Stada,  in  North  Germany ;  he  considers  these 
moulds  to  be  the  same  species  which  Klein  figured  as  Conulus  globulus,  C.  nodus,  and 
C.  nodosa  in  his  '  Dispositio  Echinodermatum,'  Tab.  XIII,  fig.  d — h.  The  specimen 
with  the  shell  was  a  unicum  and  has  been  valuable  as  helping  us  to  a  knowledge  of  the 
moulds  which  have  occasioned  so  much  confusion  in  our  synonymy. 

Mr.  S.  Woodward,  Sen.,  in  his  '  Memoir  of  the  Geology  of  Norfolk,  has  figured  two 
varieties  of  this  Urchin  as  Galerites  vulgaris,  a,  /3.  The  specimens  Mr.  Bone  has  drawn 
for  this  work  were  obtained  from  the  same  chalk  pits  as  those  from  whence  Mr.  Woodward's 
fossils  were  collected,  and  these  Norwich  specimens  agree  so  well  with  Desor's  figure  that 
there  is  no  doubt  about  their  identity  with  M.  de  Luc's  Urchin. 

M.  d'Orbigny,  in  his  '  Palseontologie  ErangaisCi'  described  and  figured  tins  species 
under  the  name  Echinoconus  globulus,  Klein,  which,  I  admit,  would  have  been  correct  in 
accordance  with  the  principle  of  priority  which  has  guided  our  nomenclature  of  species 


228  ECHINOCONUS 

had  only  one  species  been  so  named,  but  as  Klein  described  three  species  out  of  what 
now  appears  to  be  mere  varieties  of  one  form  in  my  judgment  it  is  wiser,  for  the  sake  of 
clearnesss  and  precision,  to  avoid  the  revival  of  either  of  his  names,  as  it  is  uncertain  to 
which  variety  the  name  glohulm  should  be  strictly  applied. 

In  order  to  define  accurately  this  species,  I  have  determined  to  adopt  Professor 
Desor's  figures  and  description  as  the  type  retaining  the  specific  name  abbreviata  without 
reference  to  the  mould  to  which  it  was  first  applied. 

The  test  is  round,  not  angular  at  the  border,  moderately  elevated;  convex  or 
subconoidal,  a  little  wider  anteriorly,  its  greatest  latitude  being  across  the  antero-lateral 
ambulacra,  the  sides  are  unequally  inflated,  the  posterior  half  being  more  protuberant 
than  the  anterior  half,  owing  to  the  apical  disc  being  excentral  and  situated  a  little  forwards 
(PI.  LII,  fig.  2  c,  PI.  LIII,  fig.  1) ;  the  base  is  flat,  the  mouth-opening  small,  round,  and 
prominent ;  the  vent  larger  and  opening  into  a  recurved  prominence  formed  by  the  single 
inter-ambulacrum  (PI.  LII,  fig.  2  b,  d). 

The  ambulacral  areas  are  narrow  (PI.  LII,  fig.  2  e)  and  built  up  of  a  column  of 
small  plates,  of  which  four  correspond  in  height  to  one  inter-ambulacral,  the  outer  border 
of  each  pair  of  microscopic  pedal  plates  are  united,  and  in  each  of  these  a  pair  of  pores 
are  set  obliquely.  The  anatomy  of  the  pedal  plates  forming  the  poriferous  zones  is  more 
satisfactorily  exposed  in  the  specimen  now  under  examination  than  I  have  hitherto  seen 
them,  and  clearly  shows  that  the  poriferous  zones  are  a  portion  of  the  test  distinct  from  the 
plates  forming  the  inter-ambulacra  and  ambulacra  between  which  they  are  interposed,  each 
pair  of  holes  being  formed,  for  the  passage  of  the  tubular  feet,  by  the  growth  of  a  pair 
of  plates  around  the  exertile  pedal  suckers. 

The  inter-ambidacral  areas  are  three  times  the  width  of  the  ambulacral ;  on  each 
plate  are  three  horizontal  rows  of  tubercles,  four  or  five  in  each  row  (fig.  2  e),  each 
is  surrounded  by  a  sunken  areola,  encircled  by  granules ;  the  boss  is  crenulated,  and 
the  summit  of  the  tubercle  perforated  (fig.  2,  (/,  h).  The  entire  surface  of  the 
plates  is  covered  with  granules  nuich  larger  and  more  numerous  than  in  any  other 
Echinoconus. 

The  base  is  flat  or  slightly  concave,  and  the  border  rounded ;  the  single  inter- 
ambulacrum  convex,  prominent,  and  recurved  at  the  margin,  where  the  circular  vent 
opens  (fig.  2  b,  d);  the  mouth-opening  is  small  and  central,  the  peristome  feebly 
diagonal  with  an  elevated  border  at  the  circumference. 

The  apical  disc  is  small,  and  its  plates  so  intimately  soldered  together  that  few 
specimens  show  the  sutures  (fig.  2  i)  ;  the  disc  is  excentral  and  inclined  forwards,  as  the 
slope  from  the  disc  to  the  anterior  border  is  shorter  than  the  slope  from  disc  to  the 
posterior  border ;  this  is  owing  to  the  great  development  of  the  single  inter-ambulacrum 
and  the  prominence  of  the  basal  portion  of  that  area  (see  PI.  LII,  fig.  2c;  and  PI.  LII, 
fig.  1).    The  two  pairs  of  ovarial  plates  are  small,  their  holes  very  large  (fig.  2  i) ;  and  the 


FROM   THE   UPPER  CHALK.  229 

small  single  plate  is  imperforate ;  the  spongy  portion  of  the  madreporiform  body  is  small, 
and  the  surface  of  the  other  plates  closely  covered  with  granules. 

One  remarkable  feature  in  the  structure  of  this  test  consists  in  the  size,  number,  and 
prominence  of  the  miliary  granules,  which  cover  the  inter-tubercular  spaces  and  form  on 
the  sides  and  upper  surface  of  well-preserved  specimens  a  thin  incrustation  which  coats  the 
plates  and  makes  the  tubercles  on  the  sides  appear  as  punctured  depressions  rather  than 
elevations  of  the  test.  PI.  LII,  fig.  2  e,  is  a  drawing  of  a  portion  of  both  areas  with 
the  zones  magnified  four  diameters,  taken  from  the  side  of  the  test ;  the  inter-ambulacral 
plates  support  three  rows  of  tubercles,  four  or  five  in  each,  which  are  situated  in  a 
depression  surrounded  by  an  areola,  and  have  some  of  their  bosses  crenulated  and 
summits  perforated  (fig.  2  g,  h).  The  ambulacra  have  four  rows  of  similar  tubercles  and 
a  like  abundance  of  close-set  granules  on  the  surface  of  their  plates.  The  tubercles  on 
the  basal  plates  are  more  numerous,  the  areolas  wider,  and  the  granules  in  a  great 
measure  absent  from  this  region  of  the  test  (fig.  2/)  where  these  large  basal  plates  are 
situated,  they  are  drawn,  magnified  four  diameters. 

The  mouth-opening  is  very  small  (fig.  2  b),  about  one  third  less  than  the  vent ;  the 
peristome  is  nearly  circular,  thickened  and  prominent  like  the  vent,  the  microscopic 
plates  of  the  inter-ambulacra  being  narrow  and  piled  on  each  other  produce  the  rounding 
and  thickening  of  the  peristome  ;  the  pores  in  the  zones  are  unigeminal  around  the 
opening.  One  remarkable  specimen  in  my  collection  enables  me  to  make  these  detailed 
observations  on  the  minute  anatomy  of  the  test  of  E.  ahbreviatus. 

Affinities  and  Differences. — This  species  resembles  E.  subrotundm  in  the  elevation  of 
the  upper  surface  and  inflation  of  the  lateral  parts.  A  comparison,  however,  of  the 
profiles  of  both  species,  as  given  in  PL  LH,  fig.  1  c,  and  fig.  2  c,  and  PI.  LHI,  fig.  1 
and  fig.  2  c,  will  show  at  a  glance  several  distinguishing  characters,  the  excentricity 
forwards  of  the  apical  disc,  the  shortness  of  the  anterior  slope,  as  compared  with  the 
greater  length  of  the  posterior,  and  the  prominence  and  recurvation  of  the  single  inter- 
ambulacrum.  In  E.  subrolundus  the  tubercles  are  larger  and  more  numerous  and  the 
miliary  granides  smaller  and  fewer,  whilst  the  reverse  forms  one  of  the  specific  characters 
of  E.  ahbreviatus ;  the  tubercles  are  small  and  sparse,  and  appear  sunk  in  the  test  by 
the  great  development  of  the  miliary  granulation  which  forms  a  thin  coating  on  the 
lateral  and  upper  portions  of  the  plates.  In  PI.  LII  both  species  are  admirably  drawn, 
and  the  minute  anatomy  of  the  tests  displayed,  so  that  a  careful  examination  of  the 
figures,  will  place  the  affinities  and  differences  between  these  confluent  forms  more  clearly 
before  the  eye  of  the  student,  than  the  most  elaborate  description  could  convey  to  the 
mind. 

Locality  and  Stratigraphical  Position. — All  the  examples  of  this  species  that  I  have 
examined  were  collected  from  the  Upper  Chalk  at  Harford  Bridge,  Trowse,  and  Trim- 
mingham,  Norfolk,  where  it  is  known  as  a  leading  fossil  of  the  Norwich  Chalk. 


230  ECHINOCONUS 


ECHINOCONUS    GLOBULUS,  BeSOT.       PI.  XLIX,  fig.  1   a—(). 

Galeeites  globulus,  Besor.      Monographie  des  Galerites,  tab.  iv,  figs.  1 — 4,  p.  18, 

1842. 
—  —  Forbes.     In  Morris,  Catalogue  of  Brit.   Foss.,  2iid  ed.,  p.  80, 

1854. 

Diagnosis. — Test  small,  nearly  globular;  base  narrow,  border  rounded;  vent 
elliptical  and  supra-marginal ;  inter-ambulacral  plates  sparsely  covered  with  primary 
tubercles. 

Dimensions. — Height,  six  tenths  of  an  inch ;  length,  eight  tenths ;  latitude,  seven  tenths. 

Description. — The  small  test  figured  in  our  PI.  XLIX  was  always  considered  to  be 
a  distinct  species  by  the  late  Dr.  Woodward ;  it  is  identical  with  the  form  first  described 
and  figured  by  Professor  Desor,  in  his  '  Monograph  on  the  Galerites  ; '  the  specimen,  in 
fact,  which  served  as  the  type  of  Desor's  figure  belonged  to  the  collection  of  M.  de  Luc, 
who  obtained  it  from  the  English  White  Chalk  ;  at  first  sight  it  appears  to  be  a  young 
specimen  of  E.  subrotundus  ;  a  closer  examination,  however,  shows  it  differs  in  essential 
points  from  that  form.  The  test  is  slightly  elongated,  and  is  nearly  globular  in  conse- 
quence of  the  narrowness  of  the  base,  and  the  rounding  of  the  border  ;  the  posterior 
carina  is  not  prominent,  the  vent  is  elliptical  and  quite  supra-marginal,  but  in  conse- 
quence of  the  rounding  of  the  border  this  aperture  is  visible  both  from  the  base  and 
upper  surface.  The  ambulacral  areas  are  built  of  very  narrow  plates  and  have  four  rows 
of  tubercles  arranged  obliquely  on  the  area,  one  tubercle  from  the  inner  row  alter- 
nating with  a  tubercle  on  the  outer  row;  the  poriferous  zones  are  very  narrow,  the 
])ores  unigeminal  and  oblique,  six  pairs  being  opposite  one  large  plate  (fig.  1  e). 

The  inter-ambulacral  areas  are  twice  the  width  of  the  ambulacral ;  each  of  the  plates 
supports  five  or  six  tubercles  arranged  in  quincuncial  order,  and  the  inter-tubercular 
surface  is  covered  with  microscopic  miliary  granules,  of  which  a  capital  sketch  is  given  in 
fig.  \  e  ;  at  the  border  and  base  the  granules  I'orni  regular  circles  around  the  tubercles, 
as  seen  in  fig.  1  y.     Both  these  drawings  are  magnified  six  diameters. 

The  apical  disc  is  large  and  well  developed  in  this  small  Urchin  (fig.  1  /) ;  the  right 
antero-lateral  ovarial  is  the  largest  plate  in  the  disc  and  extends  into  the  centre ;  it  is 
covered  with  the  spongy  body,  and  the  other  three  ovarials  forming  the  two  pairs 
are  small  and  of  the  same  size ;  they  are  perforated  near  their  apices,  and  the 
small  posterior  single  ovarial  is  imperforate;  the  five  ocular  plates  are  all  well 
perforated. 

The  mouth-opening  is  small  and  central,  and  the  peristome  less  in  diameter  than 
the  supra-marginal  eUiptical  vent. 

Affinities  and  Differences.  — The  globular  shape  of  this  Urchin  resembles  some  forms 


FROM  THE  UPPER  CHALK.  231 

of  E.  subrotundas,  of  which  it  may  be  only  a  variety  ;  it  has,  however,  fewer  tubercles  on 
the  inter-ambulacral  plates,  and  the  vent  is  much  higher  up  on  the  test  than  in  that 
species.  Its  globose  form  presents  a  remarkable  contrast  to  the  conical  E.  conicus,  the 
elongated  E.  castanea,  and  the  recurved  posterior  base  of  E.  ahbreviatus. 

Locality  and  Stratip-apldcal  Fosiiion.— This  very  rare  species  is  found  in  the  Upper 
White  Chalk  with  flints  at  Gravesend  and  in  Kent.  The  test  I  have  figured  is  contained 
in  the  British  Museum. 


Gems — HoLECTYPUs,  Desor,  1S47. 

DiscoiDES  (pars),  Klein,  1734. 
EciiiNiTES  (pars),  Leske,  1778. 
Galerites  (pars),  iamarcA,  1816. 
DiscoiDEA  (pars),  Gray,  1835. 

The  Genus  Holectypus  was  established  by  M.  Desor  for  the  reception  of  those 
Discoidese  which  are  deprived  of  ribs  or  projecting  processes  on  the  inner  wall  of  the  test. 
The  species  referred  to  this  group  constitute  one  of  the  oldest  types  of  the  Echinoconidse, 
and  are  met  with  chiefly  in  the  Oolitic  rocks.  They  form,  according  to  the  views  of  the 
late  Professor  Forbes,  "  a  section  or  sub-genus  of  the  Galerites,  more  valuable  on 
account  of  their  palajontological  merits,  and  limited  distribution  in  time,  being  in  the 
main  characteristic  of  the  Oolitic  period,  than  for  the  zoological  importance  of  the 
character  of  their  organization,  which  are  rather  transitional  than  distinctive." 

The  test  is  thin,  circular,  or  sub-circular,  more  or  less  hemispherical,  conical, 
or  sub-conical,  always  tumid  at  the  sides,  and  flat  or  concave  at  the  base. 

The  ambulacral  areas  are  narrow,  straight,  and  lanceolate,  with  six  or  eight  rows  of 
small  tubercles,  of  which  the  marginal  series  only  extend  from  the  base  to  the  apex. 

The  poriferous  zones  are  narrow,  and  the  pores  are  unigeminal  throughout. 

The  inter-ambulacral  areas  are  three  times  the  width  of  the  ambulacral ;  the  laro-f^ 
pentagonal  plates  support  numerous,  small,  perforated  tubercles,  which  are  very  regularly 
arranged  in  vertical  and  concentric  rows.  They  are  raised  on  bosses  with  crenulated 
summits  and  surrounded  by  ring-hke  areolas ;  numerous  minute  granules  are  scattered 
over  the  surface  of  the  plates  and  form  circles  around  the  tubercles. 

The  mouth-opening  is  circular  and  situated  in  the  centre  of  the  base  ;  the  peristome 
is  divided  by  obtuse  notches  into  ten  equal  lobes.  The  organs  of  mastication  consisted 
of  five  jaws,  which  are  preserved  in  situ  in  one  specimen  I  collected  from  the  Forest 
Marble  of  Wilts. 


233  HOLECTYPUS 

The  anal  opening  is  large,  inferior,  infra-marginal,  rarely  marginal,  sometimes 
occupying  the  entire  space  between  the  mouth  and  the  border. 

The  apical  disc  is  nearly  central  and  vertical,  composed  of  five  ovarial  and  five 
ocular  plates  ;  the  right  antero-lateral  ovarial  is  much  the  largest  and  extends  into  the 
centre  of  the  disc ;  it  supports  a  prominent,  convex,  madreporiform  body.  In  all  the 
Oolitic  species  the  anterior  and  posterior  pairs  of  ovarials  are  perforated,  and  the  single 
plate  imperforate;  whilst  in  all  the  Cretaceous  species  the  five  ovarial  plates  are  all 
perforate,  and  the  five  ocular  plates  are  small,  triangular  bodies,  with  marginal  perfora- 
tions (fig.  1  i). 

The  internal  moulds  of  Hohdypus  want  those  depressions  occasioned  by  ribs 
projecting  from  the  inner  walls  of  the  test  which  so  well  characterise  the  genus  Discoidea. 

The  spines  are  short,  with  a  smooth  head  and  milled  ring,  and  they  have  the  surface 
sculptured  with  fine  longitudinal  lines. 

Iloledypus  is  distinguished  from  Echinocoiim  by  having  a  larger  mouth  and  vent, 
a  concave  base,  and  a  less  elevated  dorsal  surface;  and  from  Discoidea  in  having 
tumid  sides,  a  larger  mouth  and  vent,  and  the  absence  of  ribs  from  the  internal  walls 
of  the  test. 

The  small  crenulated  tubercles  and  basal  vent,  with  the  absence  of  any  aperture 
in  the  upper  surface  of  the  inter-ambulacrum,  distinguishes  Iloledypus  from  P yg aster ; 
and  the  want  of  a  longitudinal  valley  in  the  inter-ambulacrum  separates  Iloledypus  from 
Hyboclypus  and  Galeropygus. 

The  Genus  Iloledypus  is  most  abundant  in  the  Oolitic  rocks;  the  Cretaceous 
rocks  of  France  contain  seven  species :  one  is  special  to  the  Neocomian,  one  to  the 
Aptien,  three  to  the  Cenomanian,' and  two  to  the  Turonian  stages.  I  now  add  a  new 
species  from  the  Chloritic  Marl  of  England,  and  the  first  of  this  genus  from  the  chalk 
found  in  the  British  Islands. 

The  Genus  Holedypus  forms  two  natural  groups,  both  organically  and  stratigraphically 
distinct  from  each  other.  The  apical  disc  in  one  group  has  only  four  of  the  ovarial 
plates  perforate ;  in  the  second  group  all  the  five  ovarials  are  so.  The  species  with  the 
four  perforate  ovarials  are  all  Jurassic,  and  those  with  the  five  perforate  ovarials  are 
Cretaceous. 


FROM  THE  CHLORITIC  MARL.  233 


HoLECTYPUS  BiSTRiATUS,  Wright,  sp.  IIOV.     PI.  LXV,  fig.  3  a,  h,  c. 

Diapiosis. — Test  sub-circular,  sub-conoidal,  depressed  on  the  upper  surface,  and 
flattened  at  the  base  ;  ambulacra  lanceolate,  with  four  irregular  rows  of  small  tubercles ; 
poriferous  zones  straight,  narrow,  with  a  smooth  nude  band  extending  from  the  disc  to  the 
border  on  the  inter-ambulacral  side  of  each  zone.  Inter-ambulacra  wide,  plates  narrow, 
with  horizontal  rows  of  small  tubercles  on  each,  apical  disc  small. 

Dimemions. — Height  eight  tenths  of  an  inch  ;  breadth  one  inch  and  eight  tenths  of 
an  inch. 

Description. — This  rare  Urchin  was  collected  many  years  ago  from  the  Chlontic 
Marl,  near  Chard,  by  Mr.  Weist,  and  kindly  communicated  for  this  work.  It  was 
long  considered  to  be  a  depressed  variety  of  Discoidea  cylindrica.  In  developing 
the  specimen,  however,  I  displaced  a  portion  of  the  test,  which  disclosed  the 
inner  surface  and  the  mould,  and  it  then  became  evident  that  the  Urchin  was  not  a 
Discoidea,  but  a  true  llolectypus,  as  it  had  none  of  the  internal  ribs  at  the  ambitus  which 
distinguish  Discoidea;  it  is  the  first  Holectypus\}i\'&X,\\^%  been  recorded  from  the  Cretaceous 
rocks  of  England. 

The  test  is  sub-circular,  thin  at  the  ambitus  and  depressed  on  the  upper  surface 
(fig.  3  U)  ;  the  ambulacral  areas  are  lanceolate,  with  four  or  six  rows  of  small  tubercles 
disposed  in  a  zig-zag  manner  on  alternate  plates  of  the  area  which  are  very  narrow,  five 
of  them  in  vertical  height  being  equal  to  one  inter-ambulacral  plate.  The  poriferous 
zones  are  narrow,  the  pores  small,  and  unigeminal,  one  pair  of  pores  corresponding  to 
one  ambulacral  plate  (fig.  8  c)  magnified  twice. 

The  inter-ambulacral  areas  at  the  ambitus  are  nearly  three  times  the  width  of  the 
ambulacra ;  the  columns  are  built  of  narrow  plates,  each  supporting  a  horizontal  row  of 
small  tubercles,  seven  to  eight  in  a  row  near  the  ambitus  and  fewer  up  the  sides,  each 
tubercle  is  surrounded  by  a  narrow  areola,  the  boss  of  which  is  crenulated  and  the 
summit  perforated.  The  only  specimen  I  have  seen  is  the  one  under  examination; 
unfortunately,  the  surface  of  the  test  is  so  much  rubbed  that  its  minute  structure  can 
only  be  made  out  by  selecting  those  parts  of  the  plates  which  are  best  preserved  for 
careful  study  with  the  glass.  The  tubercles  are  very  small  and  numerous,  and  the 
horizontal  I'ows  they  form  fill  up  the  greater  portion  of  the  surface  of  the  plates,  so  that 
the  number  of  miliary  granules  is  inconsiderable.  On  each  side  of  the  inter-ambulacra, 
separating  the  tubercular  surface  from  the  poriferous  zones,  two  smooth  nude  bands 
extend  from  the  ambitus  to  the  disc.  These  naked  calcareous  ribbons  are  very  Avell 
seen  on  one  of  the  areas,  and  this  bistriated  structure  forms  a  specific  character  of  some 
value  and  from  which  the  specific  name  is  derived. 

30 


234  ECHINONIDtE 

The  apical  disc  is  small,  and  the  five  ovarial  plates  are  all  perforated  ;  the  spongy 
body  is  unich  rubbed  and  the  ocular  plates  so  blended  with  the  other  elements  that 
their  individual  character  cannot  be  seen. 

The  base  is  covered  with  the  matrix,  which  adheres  so  firmly  to  the  test  that  it  is 
impossible  to  effect  its  separation  from  the  surface  without  at  the  same  time  removing 
the  shell.     The  anatomy  of  this  region  is,  unfortunately,  at  present  unknown. 

Affinities  and  Differences. — This  species  very  much  resembles  Holecti/jms  Cenomanensis, 
Gueranger  both  in  the  general  outline  of  the  test,  the  smallness  of  its  tubercles,  and  in  the 
manner  they  are  disposed  on  the  plates.  It  is  found  likewise  in  nearly  the  same  horizon 
of  the  Cretaceous  rocks.  The  only  difference  I  can  detect  is  the  presence  of  the  nude 
ribbon-like  bands  on  the  outer  side  of  the  poriferous  zones,  no  indication  of  which  is 
given  in  M.  Cotteau's  beautiful  and  carefully  drawn  figures. 

Locality  and  Stratigraplncal  Position. — Collected  from  the  Chloritic  Marl  near 
Chard,  with  Catoj)ygus  cohimbarius,  Pyrina  DesmouUnsii,  Cottaldia  Benettits,  and  other 
Upper  Greensand  forms. 


Family  7. — Collyritid^,  d'Orhigny,  1853  (not  yet  found  in  British 

Cretaceous  strata). 


Family  8. — EcHiNONiDiE,  Wright,  1856. 

Test  thin,  oval ;  poriferous  zones  narrow,  meeting  at  the  apical  disc ;  pores  unigeminal ; 
tubercles  of  both  areas  nearly  equal  in  size,  but  neither  perforated  nor  crenulated ;  spines 
stout,  subulate.  Mouth-opening  nearly  central,  irregularly  pentagonal  and  edentulous. 
Vent  oblong  or  pyriform,  basal  or  marginal,  closed  by  anal  plates ;  apical  disc  nearly 
central,  four  ovarial  plates  perforated,  one  imperforate.  Ocidars  microscopic,  tubei'cles 
small  and  imperforate. 

The  existing  forms  belong  to  the  genus  Echinoneus  of  Van  Phelsum,  instituted  under 
the  Dutch  name  Egelschcitze,  and  adopted  by  Leske,  Lamarck,  Deslongchamps, 
De  Blainville,  and  Desor,  to  include  certain  living  species  of  small  thin-shelled  Urchins, 
with  an  oval  form  and  a  rounded  and  inflated  border.  The  ambulacral  areas  are  narrow 
and  lanceolate;  the  poriferous  zones  depressed,  and  the  pores  small  and  unigeminal 
throughout ;  the  upper  surface  is  flattened,  and  the  apical  disc  small  and  excentral ;  the 
two  pairs  of  genital  plates  are  perforated,  and  the  single  posterior  plate  is  imperforate ; 
the  base  is  concave  and  curved  from  before  backwards ;  the  mouth-opening  small,  oblong. 


PROM  THE  CHLORITIC  MARL.  235 

oblique,  and  nearly  central ;  the  peristome  entire  and  without  auricles,  and  therefore 
edentulous.  A  diagnostic  character  of  the  family  is  the  periprocte,  which  is  basal  and 
pyriform,  about  the  same  size  as  the  peristome,  and  situated  between  the  border  and  the 
mouth.  The  tubercles  are  small  and  numerous,  disposed  in  regular  series,  and  raised  upon 
smooth  circular  elevations,  with  perforated  summits ;  in  this  we  discover  another 
organic  difference  between  the  Echinonid^  and  the  EchinoconiDjE.  The  EcHiNONiDiE 
inhabit  the  seas  of  the  Antilles,  the  Philippines,  the  Trinity,  Cuba,  Zanzibar,  and  New 
Zealand,  and  tests  of  the  same  species  are  found  in  a  semi-fossil  state  in  the  calcareous 
tufa  of  Guadeloupe,  Cuba,  and  Porto-Rico. 

The  fossil  species  are  included  in  the  genus  Pyrina,  which  are  all  found  in  the  different 
stages  of  the  Cretaceous  rocks. 


Genus — Pyrina,  Desmoulins,  1837. 
Pykina,  Globatek,  and  Nucleopygus,  Agassiz,  1837. 

Test  oval  or  round,  depressed  or  globular,  sometimes  pentagonal  or  enlarged  before  and 
narrow  behind.  Under  surface  inflated  and  often  depressed  around  the  mouth-opening, 
which  is  oval,  obhque,  and  inclined  from  the  right  to  the  left  side ;  this  aperture  is 
nearly  central,  and  destitute  of  lobes  and  auricles.  The  apical  disc  is  small,  compact, 
and  nearly  central ;  it  is  composed  of  four  perforated  genital  plates,  of  which  the  right 
antero-lateral  is  the  largest,  extending  into  the  middle,  and  supporting  the  small  niadre- 
poriform  body.  The  five  small  ocular  plates  are  closely  wedged  into  the  angles  formed 
by  the  genitals,  all  the  elements  of  the  disc  being  soldered  together.  The  vent  is  oval 
and  marginal,  in  general  nearer  the  upper  than  the  under  surface.  The  poriferous  zones 
form  straight  equal  narrow  linear  depressions,  all  composed  of  simple  pores  in  regular 
pairs  extending  from  the  peristome  to  the  disc.  The  tubercles  are  mamniillated  and 
imperforate,  larger  at  the  under  side,  and  the  inter-tubercular  surface  of  the  plates  is 
covered  with  a  great  number  of  granules. 

Pyrina  differs  from  EcJiinoconiis  in  having  in  general  an  elongated  form,  the  apical 
disc  has  only  four  genital  plates,  the  mouth  is  oval,  oblique  and  edentulous;  the 
vent  is  marginal,  and  the  tubercles  are  imperforate,  whereas  in  EcUinoconus  the  disc  has 
five  genital  plates,  the  mouth  is  circular  or  slightly  pentagonal,  and  provided  with  denti- 
ferous  jaws ;  the  vent  is  basal  or  infra-marginal,  and  the  tubercles  are  maramillated  with 
crenulated  bosses  and  perforated  summits. 


236  PYRINA^ 


Pyrina  Desmoulinsii,  (FArcUac,  1847,  PI.  LIV,  fig.  2  a — /. 


Pykina  Desmoulinsii,  d'ArcMac.     Mem.  de  la  Soc.  Geol.  de  France,  2e  serie,  tome 
ii,  p.  297,  pi.  xiii,  fig.  4,  1847. 

—  —  Agassis  et   Besor.     Catal.    raisoime,   p.    92,   Module   T.    86, 

1847. 

—  —  d'Orbigny.     Prodrome,  t.  ii,  p.  178,  Etage  No.  651,  1847. 

—  —  Woodward.      Mem.    of    the    Geol.    Surv.,   Organic  Remains, 

Decade  v,  pi.  vi,  fig.  a,  1856. 
Pyrina  Prattii,  Forbes.     Morris  Catal.  Brit.  Foss.,  p.  88,  1854. 

—  Desmoulinsii,  d'Orlignij.     Paleontol.   Fran^aise,   tome  vi,  p.  4G7,  pi.  981, 

figs.  7 — 11,  1855. 


Diagnosis. — Test  tumid,  oblong ;  ambitus  inflated ;  posterior  border  slightly  emargi- 
nate ;  upper  surface  depressed ;  apical  disc  small,  nearly  central ;  base  concave  in  the 
middle  and  pulvinated  at  the  border ;  mouth-opening  oval,  oblique,  and  nearly  central ; 
periprocte  elliptical,  supra-marginal,  nearer  the  upper  than  the  under  surface. 

Dimensions. — Antero-posterior  diameter  one  inch  ;  lieight  half  an  inch. 

Description. — The  test  of  this  rare  Urchin  is  oblong  or  elliptical,  regidar  and 
symmetrical,  depressed  on  the  upper  surface,  inflated  round  the  sides,  and  concave  near 
the  centre  of  the  under  surface.  The  summit  is  sub-central,  nearer  the  anterior  than  the 
posterior  border.  The  ambulacral  areas  are  narrowly  lanceolate ;  the  poriferous  zones  are 
linear  and  depressed,  and  the  pores  minute,  unigeminal,  and  placed  in  obhque  pairs.  lu 
passing  across  the  base  the  geminal  pores  become  more  and  more  oblique,  until  they  fall 
into  a  single  file  and  terminate  around  the  peristome.  The  plates  of  both  areas  support 
a  number  of  small  equal-sized  tubercles ;  in  fig.  2  e  is  shown  their  mode  of  arrange- 
ment on  the  ambulacral  and  inter-ambulacral  areas ;  they  have  a  quincuncial  disposition  on 
the  plates.  The  areal  space  around  each  is  sharply  defined,  the  tubercle  is  raised  on  a  boss, 
and  its  summit  is  perforated.  The  intermediate  surface  of  the  plates  is  covered  with  a 
very  fine  microscopic  granulation  (fig.  ^  (/).  The  tubercles  at  the  base  are  much  more 
developed  than  those  on  the  upper  surface  of  the  test.  Fig.  2  h  and  fig.  2  i  show  the 
basal  tubercles  magnified ;  the  areal  space  is  deeply  excavated  out  of  the  structure  of  the 
plate,  and  the  tubercle  is  larger  than  those  on  the  upper  surface  at  fig.  2  i.  A  portion  of 
the  test  near  the  mouth-opening  is  shown  with  the  arrangement  of  the  zones  and  the 
disposition  of  the  tubercles  in  this  region. 

The  mouth-opening  is  large,  elliptical,  elongated  in  the  direction  of  its  greatest  axis, 
slightly    oblique  (fig.  2  h),    and    situated    immediately    beneath  the     organic  summit. 


FROM  THE  CHLORITIC  MARL.  237 

The  vent  is  elliptical,  and  placed  in  the  middle  of  the  posterior  border  (fig.  2  d), 
Jiearer  the  upper  than  the  under  surface  (fig.  2  a). 

The  apical  disc  is  small,  and  composed  of  four  ovarial  plates,  of  which  the  right 
antero-lateral  is  much  the  largest,  and  supports  a  spongy  madreporiform  body.  All  these 
plates  are  perforated  (fig.  2/).  The  ocular  plates,  five  in  number;  are  small,  and  well 
wedged  in  between  the  ovarials. 

Affinities  and  Differences. — The  regular  elliptical  elongated  form  of  Pi/rina  JDesmou- 
linsii,  with  its  flattened  upper  surface  and  pulvinated  base^  distinguish  this  species  from 
its  congeners.  I  have  compared  specimens  obtained  from  the  Btage  Cenomanien  of  the 
environs  of  Tournay,  Belgium,  with  specimens  collected  from  the  Chloritic  Marl  at 
Chard,  and  find  them  to  be  identical  in  all  their  details.  It  very  much  resembles  Pi/rina 
ovidtim,  which,  however,  is  a  smaller  form,  with  a  more  inflated  test,  and  the  elliptical 
vent  is  situated  near  the  dorsum.  Compare  fig.  2  and  fig.  3,  where  the  affinities  and 
differences  are  well  shown  in  the  admirable  figures  in  PI.  LIV. 

It  difiers  from  Pyrina  lavis  in  having  a  nari'ower  test  of  a  more  regular  elliptical 
figure,  and  wants  the  inflation  of  the  anterior  portion  and  the  tapering  of  its  posterior 
border. 

Localiiy  and  StratiyrajMcal  Position. — This  rare  Urchin  was  collected  by  Mr.  Weistj 
in  the  Chloritic  Marl,  near  Chard,  and  Mr.  Pratt  obtained  another  from  the  same  locality 
and  stratum,  which  has  been  beautifully  figured  in  the  '  Memoirs  of  the  Geological 
Survey,'  Decade  v,  i)l.  vi.  The  short  description  was  from  the  pen  of  my  old 
esteemed  friend  Dr.  Woodward,  to  whom  I  forwarded  all  ray  materials  when  he  was 
engaged  in  writing  the  text  for  the  description  of  pi.  vi  of  that  Decade. 


Pyrina  ovulum,  Lamarck,  sp.     PL  LIV,  fig.  3  a — h. 


NucLEOLiTES  OVULUM,  Lamarck.     Anim.  sans  vert.,  t.  iii,  p.  37,  1816. 

—  —         Beslongchamps.     Encycl.  Method.,  t.  ii,  p.  500,  1824. 

—  —         Befrance.     Die.  des  Sc.  Nat.,  t.  xxxv,  p.  213,  1825. 
Pyrina  —        Agassiz.     Cat.  Syst.,  p.  7,  1840. 

NucLEOLiTES      —         Desor.     Mon.  des  Galerites,  p.  26,  pi.  v,  figs.  35 — 37,  1842. 

—  —         A(jassizei  Desor.     Cat.  rais.  des  Rchinides,  p.  92,  1842. 

—  —         (TOrbigny.     Prodrome,  t.  ii,  p.  271,  1847. 

—  —         Morris.     Catal.  of  British  Fossils,  2  ed,  p.  88,  1854. 

—  —         Woodward.     Mem.  Geol.  Surv.,  Decade  v,  pi.  vi,  1856. 

—  —         Cotteaii.     Paleontologie  Frangaise,  pi.  985,  figs.  7 — 11,  tome 

vi,  p.484,  1855. 


238  PYRINA 

Diagnosis. — Test  small,  inflated,  depressed  at  the  upper  surface.  Ambitus  elliptical,, 
base  flattened,  margin  much  inflated ;  mouth  irregular,  pentagonal,  oblique,  situated  in 
the  middle  of  the  base  ;  posterior  border  sulcated,  vent  elliptical,  elevated  near  the  upper 
surface,  plates  closely  covered  with  small  tubercles. 

Dimensions. — Antero-posterior  diameter  four  tenths  of  an  inch ;  height  three  tenths  of 
an  inch. 

Descriptions. — The  test  of  this  rare  little  Tyrina  is  oblong-oval,  inflated,  rounded 
before,  and  sulcated  behind,  for  lodging  the  vent.  In  its  longitudinal  profile,  fig.  3  d,  the 
test  is  higher  behind  than  before,  and  always  more  or  less  truncated,  the  upper  surface  is 
convex  and  slightly  flattened,  the  under  surface  is  convex  and  pulvinated,  without  a  depres- 
sion in  the  centre,  the  plates  are  covered  with  numerous  small  tubercles  larger  on  the  under 
surface,  the  areas  are  excavated  to  receive  the  boss,  which  carries  a  small  perforated 
tubercle,  fig.  3  g  and  h.  The  apical  disc  is  small,  composed  of  four  perforated  ovarial 
plates  and  five  very  minute  oculars,  fig.  3/.  The  mouth  opening  is  situated  in  the 
middle  of  the  base,  fig.  3  c,  and  forms  an  irregular  pentagon  with  its  long  axis  oblique.  The 
vent  is  oval,  situated  in  a  sulcus  high  up  in  the  posterior  border,  and  the  periprocte  is  much 
nearer  the  upper  than  the  under  surface,  fig.  3  h,  and  fig.  3  e.  The  poriferous  zones 
are  extremely  narrow,  and  appear  like  fine  depressed  lines  on  the  surface  of  the  shell. 

Affinities  and  Differences. — This  species  differs  from  Pyrina  Desmoulinsii  in  having 
the  posterior  border  sulcated  for  the  vent  which  occupies  a  higher  position  in  this 
Urchin. 

Locality  and  Stratigraphical  Position. — It  is  said  to  have  been  collected  from  the 
lower  chalk  of  Dorsetshire.  In  France  M.  Cotteau  records  it  from  I'fitage  Senonien,  he 
collected  it  in  that  formation  at  Saint  Christophe,  and  at  Tours,  Indre-et-Loire,  and  at 
Villedieu,  Loir-et-Cher. 


Pyrina  l^vis,  Agassis,  1840.     PI.  LIV,  fig.  1  a — e. 

Galerites  l^vis,  Agassiz.     Cat.  Syst.,  p.  7,  1840. 

—  —     Besor.     Monographic  des  Galerites,  p.  24,  pi.  iv,  figs.  8 — 11,1843. 

—  —      Agassi:.     Cat.  rais.,  p.  91,  Module  79,  1847. 

—  —      (VOrbigmj.     Prodrome,  t.  ii,  p.  272,  1847. 
EcHiNOCONUs —      d'Orbigny.     Revue  Zoologique,  p.  21,  1854. 

Pykina  —      Cotteau.     Paleontol.  Francaise,  t.   vi,  p.  490,  pi.  987,  figs.  6 — 9, 

1855. 


Diagnosis. — Test   subpentagonal,   enlarged   anteriorly    and    contracted   posteriorly, 


FROM  THE  UPPER  GREENSAND.  239 

■convex  above,  inflated  at  the  sides  and  flattened  below;  vent  large,  supra-marginal, 
elliptical ;  mouth-opening  central,  opposite  the  disc ;  tubercles  small,  surface  of  the  plates 
smooth. 

Dimensions. — Anterior  posterior  diameter  eleven  twentieths  of  an  inch  ;  height  seven 
twentieths  of  an  inch. 

Description. — This  little  Urchin  appears  to  be  a  very  rare  form,  as  the  example  before 
me  is  the  only  specimen  I  have  seen  in  English  collections  ;  the  type  specimen  figured  by 
my  friend  Professor  Desor,  in  his  Monograph  on  the  Galerites  belonged  to  M. 
Deshayes  and  was  the  only  one  known  to  him. 

M.  Cotteau  has  not  seen  the  original,  giving  copies  of  Prof.  Desor's  figure  of  the  test 
and  quoting  his  description  of  its  structure  in  his  '  Paleontologie  Francaise.'  My 
specimen  was  collected  several  years  ago  from  the  Upper  Greensand  near  Chute  farm, 
Wilts,  along  with  some  fine  examples  of  Catopygiis  colmnharius  and  Cottaldia  Benettice, 
so  that  there  is  no  doubt  of  the  horizon  of  the  English  specimen.  The  general  outline 
of  the  test  is  indistinctly  pentagonal,  enlarged  before  and  slightly  narrower  behind  (fig.  1  h 
and  fig.  1  c).  The  upper  surface  is  convex,  the  sides  inflated,  and  the  base  flat  (fig.  1  a ; 
fig.  1  e) ;  its  height  is  about  one  half  the  length  of  the  test.  The  plates  are  covered  with 
small  tubercles,  which  are  very  indistinctly  seen  ;  those  at  the  base  are  larger.  The  vent 
occupies  the  middle  of  the  border ;  the  periprocte  is  large,  of  an  elliptical  shape,  and 
placed  a  little  nearer  to  the  base  than  the  upper  surface.  The  sur-anal  carina  is  only 
slightly  developed  around  the  lower  part  of  periprocte.  The  lower  surface  is  nearly  flat, 
with  the  margin  round,  and  the  small  mouth-opening  is  situated  in  the  middle  of  the 
base  directly  opposite  the  vertex. 

Affinities  and  Differences. — This  species  is  readily  distinguished  from  Pyrina 
Desmoulinsii  by  its  sub-pentagonal  form  enlarged  before  and  contracted  behind;  its 
sides  are  likewise  more  inflated  and  the  lower  angle  of  the  periprocte  is  nearest  the  base, 
whilst  in  P.  Desmoulinsii  the  upper  angle  of  that  aperture  is  nearest  the  dorsal  surface. 

Locality  and  StratiyrapJdcal  Position. — I  collected  this  Urchin  from  the  Upper 
Greensand  of  Chute  Farm,  near  Wilts,  with  Catopyyus  columbariiis,  Cottaldia  Benettice, 
and  other  well-known  forms  of  Urchins  and  Mollusca  belonging  to  that  stratum. 

The  type  figured  by  M.  Desor  was  obtained  from  the  Cretaceous  rocks  of  France,  and 
as  it  was  communicated  to  M.  Desor  by  M.  Deshayes  without  the  indication  of  the  forma- 
tion from  whence  it  was  collected,  we  are  unfortunately  in  ignorance  of  its  stratigraphical 
position,  and  as  M.  Cotteau  had  not  seen  the  specimen,  he  was  unable  to  give  an  opinion 
on  the  matrix. 


240 


CATOPYGUS 


family  9 — Echinobrissid^,  Wri(/]d,  1856. 

Test  thin,  circular,  oblong,  sub -pentagonal,  or  clypeiform,  covered  with  microscopic 
perforate  or  imperforate  tubercles,  surrounded  by  excavated  areolas  ;  ambulacra  narrow, 
enclosed  by  poriferous  zones  more  or  less  petaloidal ;  pores  set  at  different  distances  apart, 
and  imited  by  connecting  sutures.  Mouth-opening  small,  nearly  central,  pentagonal, 
edentulous,  and  in  general  surrounded  by  five  lobes.  Vent-opening  in  a  sulcus  in  the 
upper  surface  of  the  single  inter-ambulacrum,  or  in  a  marginal  depression  or  basal 
portion  thereof;  apical  disc  small,  with  four  perforate  and  one  imperforate  genital  plate ; 
ocular  plates  very  small ;  madreporiform  body  extending  into  the  centre  of  the  disc. 
This  family  is  extremely  numerous  in  genera  and  species  ;  two  of  its  representative  forms 
are  still  living — Echinobrissus  recens,  Edwards,  in  the  Antilles,  and  Cassidulus  Australus,. 
Lamarck,  in  the  Australian  seas. 

I  include  the  following  genera  in  this  natural  family  : 


Catopygtjs,  Agassis. 
Clypeopygus,  d"  Orbi(/ny. 
Clypeus,  Klein. 
Echinobrissus,  Breyniiis. 
Phyllobrissus,  Cotteau. 


BoTRioPYGUS,  d'  Orhigny. 
Trematopygus,  d'Orbiyny. 
Rhynchopygus,  d'  Orbiyny. 
Cassidulus,  LamarcJc. 
Caratomus,  Jyassiz. 


Genus — Catopycus,  Jyassiz,  1837. 

NucLEOLiTES,  Lamarck,  Goldfuss. 

JDiaynosis. — Test  oval  or  elongated,  in  general  inflated,  narrower  anteriorly  than 
posteriorly ;  upper  surface  convex,  summit  excentrical  anteriorly ;  under  surface  flat  or 
slightly  convex,  and  rounded  at  the  border ;  posterior  half  of  the  test  much  higher  and 
wider  than  the  anterior  half;  vent  situated  in  the  posterior  border;  periprocte  small, 
round,  or  oval,  placed  high  in  a  prominent  projection  of  the  inter-ambulacrum  at  the  summit 
of  a  vertical  truncation  of  the  area.  Mouth-opening  small,  situated  nearer  the  anterior 
than  the  posterior  border ;  pentagonal  in  form  with  equal  elongated  sides,  having  one  angle 
anterior,  and  surrounded  by  five  prominent  lobes  (PI.  LV,  fig.  2  h) ;  between  the  lobes 
a  rosette  is  formed  of  five  depressed  leaves,  crowned  with  minute  granules  and  unequal 


FROM  THE   UPPER   GREENSAND.  241 

buccal  pores,  some  double  externally,  others  small  internally.  Ambulacra  narrow, 
sub-petaloid,  straight,  more  or  less  elongated,  and  open  at  the  lower  extremity ;  poriferous 
zones  composed  of  an  inner  series  of  round  pores,  and  an  external  series  of  elongated 
pores  arranged  in  conjugate  pairs  (fig.  2  cj) ;  tubercles  very  small,  raised  on  mammillated 
bosses  (fig.  2)  in  many  horizontal  lines  on  the  surface  of  the  dorsal  plates,  those  at  the 
base  being  larger.  Apical  disc  small,  prominent,  formed  of  four  perforated  ovarial  plates 
and  five  microscopic  oculars,  the  madreporiform  body  projecting  from  the  surface 
(fig.  2/). 

Affinities  and  Differences. —  Calopi/pis  differs  from  Cli/jjeopi/ijus  and  Echinohrissus  by 
its  oval  form,  convexity  of  the  upper  surface,  inflation  of  the  sides,  and  flatness  of  the  base, 
by  its  pentagonal  mouth,  with  five  prominent  sides  and  rosette  of  pores  between  the 
lobes,  and  its  small  round  periprocte  opening  high  in  a  prominent  vertical  truncation  of 
the  single  inter-ambulacrum. 

The  genus  Catopygii,s  appertains  to  the  Cretaceous  rocks,  and  is  a  very  characteristic 
fossil  in  its  different  divisions.  In  the  Gault  or  Albiau  stage  of  the  Mediterranean  basin 
Catopi/ffus  ci/IindricHs  has  only  hitherto  been  found. 

In  the  Upper  Greensand  or  Cenomanian  formation  C.  columharius  prevails  throughout 
the  Anglo-Parisien  and  Mediterranean  basins. 

In  the  Lower  Chalk  or  Turonian  C.  EhraijanusK?,  found. 

In  the  Middle  Chalk  or  Senonian  eight  species  have  been  collected  in  France,  Avhere 
many  of  the  beds  of  this  division  attain  a  development  unknown  in  England,  and  contain 
a  fauna  of  the  most  remarkable  forms.  The  C.  suh-carinahis  and  ehngahis  are  found 
simultaneously  in  the  Anglo-Parisian  and  Pyrenean  basins,  although  C.  Icevis,  fenes- 
tratus,  conformis,  pyriformis,  ohtusus,  and  affinis,  are  discovered  only  in  the  Parisian  basin. 

This  genus,  therefore,  attained  its  greatest  development  in  the  seas  which  deposited 
the  White  Chalk  with  flints,  and  became  extinct  with  the  close  of  the  Cretaceous  epoch, 
as  Catopiygus  is  not  found  in  the  Tertiary  rocks  nor  in  the  waters  of  the  present 
time. 


Catoptgtjs  columbarius,  LamarcJc,  1816.     PI.  LV,  fig.  2  a — i. 

EcHiNiTEs  PYRiFOEMis,       ParMnson.     Organic  Bemaius,  vol.  iii.tab.iii,  fig.  G,  ISll. 
NucLEOLiTES  coLUMB.iiiiA,  Lamarck.     Anim.  sans  Vertebres,  t.  iii,  p.  37,  1816. 

—  —  Deslonffchamj).     Encyl.  Method.,  t.  ii,  p.  .5/0,  1824. 

—  —  De/rance.     Die.  des  Sciences  Nat.,  t.  xxxv,  p.  313,  182.5. 

—  CAiuNATUS,     Goldfuss.     Petrefacta  Germanise,  b.  i,  p.  142,  pi.  xliii,  fig. 

11,  1826. 

—  coLUMBAKiA,  BlainvUle,     Die.  des  Sciences  Nat.,  t.  Ix,  p.  188.  1830. 

31 


242  CATOPYGUS 

Catopygus  carinatus,        Agasdz.     Prodrome  Echinides,  p.  18,  1836. 
NucLEOLiTES  COLTJMBAKIA,  DesmouUns.     Etudes  sur  les  Echinides,  p.  356,  1837". 

—  CARINATUS,     d'Archiac.     Mem.  Geol.  Soc.  de  France,  p.  180,  1837. 
Catopygus  —  Bronn.     Letbse  Geognostica,  p.  G13,  1837. 

—  —  Milne-Edwards.     In  Lamarck,  2e  ed.,  t.  iii,  p.  351,  1840. 
NnCLEOLITES  COLUMBARIA,  Ibid.      Ibid.,  344. 

Catopygus  carinatus,        Agassiz.     Cat.  Syst.,  p.  4,  1840. 

—  —  Roemer.     Norddeuts-Kreide-Gebirges,  p.  32,  1840. 
Catopygus  CARINATUS,        Morris.     Catalogue  of  British  Fossils,  p.  49,  1843. 

—  coLUMBARius,    d'Archiac.     Mem.  Soc.  geol.  France,  p.  296,  1847. 

—  —  Ayassiz  et  Desor.      Cat.   raison.,  p.  100,   Modele  R  71 

1847. 

—  —  d'Orbigny.     Prod.,  t.  i,  p.  1/8,  Stage  20,  1847. 
NucLEOLiTES  CARiN.iTUS,     Forbes.     Mem.  Geol.  Surv.,  Decade  i,  pi.  1 0,  1849. 
Catopygus             —  Sorignet.     Oursins  del'Eure,  p.  43,  1850. 
NucLEOLiTES          —  Quenstedt.      Handbuch   der   Petrefact.,  p.  586,  pi.   xlix, 

fig.  51,  1852. 
Catopygus      •      —  Bronn.     Leth.  Geogn.,  2  ed.,  p.  196,  pi.  29^,  fig.  16,  1852. 

—  —  Albin  Gras.     Catal.  des  Corps  org.  de  I'Isere,  p.  40, 1852. 

—  —  Morris.     Catal.  of  British  Fossils,  2  ed,  p.  74,  1854. 

—  COLUMBARIUS,  Co^ieaM.    Pal.  Frang.  Ter.  Cret.,  t.  vi,  p.  436,  pi.  970, 1855. 


Diapiosin. — Test  oval  or  subrotund,  contracted  anteriorly,  enlarged  and  truncated 
posteriorly,  sides  inflated,  dorsal  surface  unequally  convex,  base  nearly  flat,  ambulacra 
narrow,  dorsal,  subpctaloid  and  open  below;  inter-ambulacra  wide,  single  inter-ambulacrum 
narrow,  elevated,  and  truncated,  vent  round  in  the  upper  border,  above  the  periprocte 
an  obtuse  carina  which  terminates  in  the  projecting  upper  border  of  the  vent ;  mouth- 
opening  small,  excentral  nearer  the  anterior  border,  peristome  surrounded  by  five  prominent 
lobes  and  a  rosette  of  pores  between  them.  Apical  disc  excentral  nearer  the  anterior 
border,  the  vertex  in  general  behind  the  apex. 

Dimensions. — I  have  selected  six  good  typical  forms  showing  the  varying  proportions 
of  this  species. 


1 

2 

3 

4 

5 

6 

Length 

1 

fill 

nio 

"l2 

OA 

OA 

Ol^2 

Height     . 

AJ-O 
^12 

m 

^12 

OA 

OA 

o-A 

Breadth    . 

0  ^ 

Oi^ 

0  ^ 

»^12 

OA 

OA 

Ox^ 

Description. — The  table  of  synonyms  exhibits  the  changing  views  of  naturalists  in 
respect  to  this  beautiful  Urchin.  Goldfuss,  who  gave  the  first  good  figure  of  the  species, 
cites,  with  doubt,  its  identity  with  Nucleolites  colmnharius,  Lamarck,  but  the  brief  diagnosis 
in  '  Hist.  Nat.  des  Anirn.  sans  Vert.,'  taken  in  connection  with  the  locality  and  stratum 
from  whence  it  was  collected,  "  les  environs  de  Mans/'  so  well  known  for  its  beautiful  Upper- 


PROM  THE  UPPER  GREENSAND.  243 

Greensand  fossils,  has  satisfied  me,  after  a  comparison  of  specimens  in  my  collection  from 
that  locality  with  a  series  of  type  tests  from  the  Upper  Greensand  of  Wilts  and  Dorset,  that 
the  two  Urchins  appertain  to  the  same  species,  and  that  Lamarck's  name  ought  to  be 
retained.  Catojiygus  columbarius,  it  is  true,  assumes  a  considerable  variation  of  form  as 
regards  the  elongation,  shortening,  height,  breadth,  and  inflation  of  the  test,  so  that  there 
is  field  enough  for  species-makers,  who  attach  undue  importance  to  these  characters,  to  make 
several  varieties  out  of  a  handful  of  specimens.  These  phases  of  form  appear  to  me  to 
have  depended  on  the  physical  conditions  which  surrounded  the  life  of  the  Urchin,  and 
have  nothing  whatever  to  do  with  the  specific  characters  I  have  pointed  out  in  my 
diagnosis  of  the  species. 

The  test  is  ovate  or  subrotund  and  always  wider  behind  than  before;  the  dorsal 
surface  is  tumid,  varying  in  the  degree  of  its  elevation  ;  in  some  specimens  it  is  sub- 
depressed  and  declines  anteriorly,  in  others  it  is  subconic  and  much  elevated  in  the  centre, 
the  true  apex  being  almost  the  apical  disc,  whereas,  in  general,  that  body  is  excentral  and 
situated  before  the  vertex,  which  is  formed  by  the  ridge  of  the  single  inter-ambulacrum. 
The  sides  are  rounded  and  more  or  less  inflated,  and  the  posterior  extremity  is  truncated 
more  or  less  abruptly.  A  more  or  less  developed  obtuse  central  elevation  extends  along 
the  ridge  of  the  single  inter-ambulacrum  to  the  upper  border  of  the  vent,  where  it  forms 
in  many  examples  a  prominent  apicnlated  arch  over  the  periprocte,  PI.  LV,  fig.  2  d.  In 
all  the  specimens  I  have  examined  this  prominence  exists,  but  its  degree  of  development 
varies  much.  The  ambulacral  areas  are  narrowly  lanceolate,  limited  to  the  dorsal  surface* 
subpetaloid,  and  very  uniform  in  their  proportions  in  all  the  varieties.  The  single  area 
and  anterior  pair  are  nearly  equidistant  from  each  other,  but  the  posterior  pair  are  more 
distant  from  the  anterior  pair,  and  are  placed  much  closer  together  than  the  others  and  extend 
backwards.  The  number  of  pairs  of  pores  in  each  zone  is  nearly  equal,  varying  from 
twenty-eight  to  thirty  in  well-grown  adult  shells ;  the  pores  in  the  outer  row  are  elongated 
and  oblique,  and  in  the  inner  pores  are  round  and  appear  to  be  conjugated  by  fine 
olilique  sutures.  At  the  lower  part  of  the  petals  the  pores  become  smaller,  and  are  set 
much  wider  apart  as  they  pass  round  the  border  of  the  test  and  extend  to  the  peristome. 
The  ambulacral  plates  are  narrow  in  the  petaloid  portion  of  the  zones,  and  become 
much  larger  and  broader  beyond  the  petals ;  each  plate  has  its  pair  of  holes  which 
can  be  distinctly  traced  in  good  specimens,  and  they  form  the  true  poriferous  zones  on 
the  sides  and  base  of  the  test.  PI.  LV,  fig.  2  h,  c,  d,  <?,  shows  these  poriferous  zones. 
Around  the  mouth  the  pairs  of  pores  again  form  petals  as  on  the  dorsal  surface,  and  they 
are  here  so  arranged  that  they  form  ten  short  petaloidal  ambulacra,  forming  rosettes 
around  the  mouth,  and  constructed  like  those  on  the  dorsal  surface.  Fig.  2  h  shows  this 
structure  extremely  well  in  a  drawing  magnified  six  diameters. 

The  wide  inter-ambulacral  areas  arc  formed  of  large  oblong  plates,  the  surface  of 
which,  as  well  as  those  of  the  ambulacra,  are  covered  with  minute  moniliform  tubercles, 
interspersed  with  microscopic  granules.     Pig.  2  g  shows  the  arrangement  of  the  tubercles 


244  ■  CATOPYGUS 

and  granules  on  the  ambulacral  and  inter-ambulacral  areas  magnified  six  times  ;  and 
fig.  2  exhibits  the  more  developed  form  the  tubercles  assume  on  the  basal  plates,  and  the 
manner  they  are  encircled  by  rows  of  granules.  It  is  only  on  very  fine  specimens,  such 
as  some  I  have  obtained  from  the  Chloritic  Marl  of  Chard,  that  I  have  been  able  to  see  the 
surface  anatomy  of  the  plates,  such  as  I  have  figured  and  described  it;  the  Upper- Greensand 
fossils  are  spoiled  by  the  matrix,  and  are  quite  unfit  for  such  minute  observations. 

The  small  apical  disc  is,  in  general,  excentral,  and  the  madreporiform  body  occupies 
the  centre,  covers  the  plates,  and  forms  a  prominence ;  there  are  four  perforated  genital 
plates,  and  five  distinct  ocular  plates  (fig.  2  h  and  fig.  2  /).  The  two  anterior  genital 
holes  are  placed  nearer  together  than  the  posterior  pair. 

The  ventral  surface  is  slightly  convex,  or  nearly  flat;  the  tubercles  are  much  larger  in 
this  region,  and  exhibit  the  arrangement  shown  in  fig.  2  i,  where  each  tubercle  rises  on 
the  surface  of  a  rounded  boss  and  is  encircled  by  a  ring  of  granules  (fig.  2  c).  The 
mouth-opening  is  excentral  and  nearer  the  anterior  border,  the  peristome  is  pentagonal  and 
surrounded  by  five  prominent  tubercles  which  form  the  termination  of  the  inter-ambulacral 
areas  (fig.  2  c).  From  the  inter-lobular  spaces  ten  short  petaloid  ambulacra  proceed,  and 
these  collectively  form  rosettes  around  the  peristome,  as  shown  in  fig.  2  h,  where  this 
structure  is  drawn  magnified  six  diameters. 

The  vent  opens  in  the  upper  portion  of  the  truncated  posterior  border  in  a  well- 
defined  vertical  area;  it  is  oblong,  and  varies  in  size  in  different  specimens,  but  is  always 
small  in  proportion  to  the  size  of  the  test. 

The  periprocte  is  prominent,  especially  in  the  upper  border,  which,  in  some  specimens, 
overhangs  the  vent  in  a  beak-shaped  fashion  (fig.  2  ^). 

Affinities  and  Differences. — This  species  is  found  in  the  Upper  Greensand  or 
Cenomanian  stage  throughout  the  Anglo-Parisian  and  Mediterranean  basins,  and  it  is  the 
only  form  of  Catojjygus  hitherto  collected  in  this  stratum  in  England ;  its  characters  are  so 
definite  and  distinct  that  there  is  no  difficulty  in  distinguishing  this  species  from  its 
congeners. 

Locality  and  Stratigraphical  Position. — It  has  been  collected  from  the  Upper  Green- 
sand of  Warminster  and  Chute  Parm,  Wiltshire ;  Ilythe,  Kent ;  and  from  the  junction  beds 
of  Upper  Greensand  and  Chalk-marl  at  Maiden  Bradley,  Wiltshire  ;  and  from  the  Chloritic 
Marl,  near  Chard,  whence  my  best  specimens  were  obtained.  The  foreign  distribution  of 
this  species,  according  to  M.  Cotteau,  is  from  the  Cenomanian  or  20th  stage  of  d'Orbigny, 
the  equivalent  of  the  Upper  Greensand  of  English  authors.  In  France  it  is  common  at 
Mans,  Coulaines,  Saint-Calais,  and  Condrecieux,  Sarthe ;  Villers,  Trouville,  Calvados ; 
Havre,  Seine-Inferieure  ;  Grace,  Orne  ;  Vierzou,  Cher;  Chinon,  Indre-et- Loire  ;  Fouvas 
and  Bel-Air,  near  Pvochcfort,  and  other  localities.  In  Belgium  in  the  Tourtia  of  Tournay  ; 
in  WestphaUa  at  Essen  on  the  Ruhr. 


PROM  THE  LOWER  GREENSAND.  245 


Catopygus  Vectensis,  Wrif/Jif,  nov.  sp.     PL  LV,  fig.  1  a — d. 

Diagnosis. — Test  oblong,  contracted  posteriorly  ;  dorsal  surface  flat  and  convex, 
elevated  towards  the  narrow  posterior  border;  sides  inflated,  base  concave;  ambulacra 
narrow,  lanceolate,  dorsal,  subpetaloid,  and  open  below ;  inter-ambulacra  wide,  single 
inter-ambulacrum  narrow,  slightly  elevated  ;  posterior  l)order  truncated ;  vent  oblong, 
in  the  upper  third ;  an  obtuse  elevation  of  the  dorsal  portion,  bifurcating  at  the 
periprocte,  sends  down  a  carina  on  each  side  of  the  vent,  which  extends  to  the 
margin.  Apical  disc  nearly  central,  four  perforated  genital  plates  ;  madreporiform  body 
small,  central. 

Dimensions. — Length  one  inch  ;  breadth  eight  tenths  of  an  inch ;  height  unknown. 

Description . — This  species  has  much  resemblance  to  certain  varieties  of  Catopygus 
columbariiis  but  a  careful  comparison  between  it  and  the  most  allied  forms  of  that 
species  shows  that  Catopggus  Vectensis  possesses  distinct  characters  of  its  own.  It  is,  I 
believe,  the  oldest  form  of  the  genus  Cafojjggus  at  present  known.  The  outHne  of  the  test 
is  nearly  a  regular  oblong,  rather  more  contracted  posteriorly  (PI.  LV,  fig.  1  a,  b).  It  is 
moderately  elevated  and  a  little  higher  at  the  posterior  border  (fig  1  c)  ;  the  sides  are 
inflated  (fig.  1  d),  and  the  base  is  concave;  this  portion  of  the  test  is  partially  covered 
by  closely  adherent  matrix  in  the  best  specimen,  and  broken  in  the  other,  so  I  must 
speak  with  reservation  regarding  the  specific  characters  of  this  region.  The  ambulacral 
areas  are  narrowly  lanceolate  (fig.  1  b,  d),  and  the  long  subpetaloid  poriferous  zones  extend 
over  the  dorsal  surface,  a  character  which  is  very  well  drawn  in  figs.  1  a,  b,  c,  d;  the 
traject  line  of  the  pores  is  indicated  by  the  sutures  in  which  they  are  placed,  but  the 
pores  themselves  cannot  be  satisfactorily  made  out  in  consequence  of  the  imperfect 
preservation  of  the  areal  plates. 

The  inter-ambulacral  areas  are  built  of  long  plates ;  those  on  the  upper  surface  had 
veiy  small  tubercles  which  appear  to  have  been  more  developed  at  the  base ;  the  posterior 
single  inter-ambulacrum  has  an  elevated  ridge  on  the  mesial  line  which  extends  to  the 
upper  border  of  the  vent  (fig.  1  o),  and  then  divides  into  two  branches  (fig.  1  d) ;  which 
descend  to  the  border,  the  whole  forming  a  kind  of  miniature  Gothic  arch,  having 
the  oblong  vent  in  its  upper  third  (fig.  1  c  and  d). 

The  apical  disc  is  nearly  central  (fig.  1  b),  and  lower  than  the  vertex  (fig.  1  c) ;  it  is 
small,  has  four  genital  holes  drilled  around  a  small  central  button-shaped  madreporiform 
tubercle. 

The  mouth-opening  is  excentral  and  anterior ;  it  is  too  much  concealed  by  hard  rock 
to  be  exposed  without  risking  the  fracture  of  the  shell,  so  the  anatomy  of  the  peristome 
cannot  be  made  out. 

Affinities  and  Differences. — This  species  differs  from  C.  cohmbarius  in  the  following 


246  CLYPEOPYGUS 

characters  : — The  shell  tapers  behind,  is  not  so  elevated,  has  a  flatter  dorsal  sui-face  and 
less  prominent  central  ridge  in  the  inter-ambnlacrum ;  the  apical  disc  is  more  central,  and' 
the  contour  indicates  a  flatter  form  with  less  inflated  sides. 

Locality  and  Stratigrapliical  Fosition. — This  new  species  was  collected  by  the  Kev. 
T.  Wiltshire,  P.G.S.,  from  the  Lower  Greensand  (Neocomian)  at  Shankhn,  Isle  of 
Wight. 


Genus — Cltpeopygus,  A.  cTOrbirjny,  1856. 

NucLEOLiTES  (pars),  Ayassh,  Besor,  Cotteau. 
EcHixoBKissus  (pars),  Be  Loriol. 
CATOPYGns  (purs),  Jffassis. 

Diagnosis. — Test  oblong,  more  or  less  depressed,  upper  surface  convex,  mider  surface 
concave,  mouth-opening  excentral,  nearest  the  anterior  border ;  peristome  surrounded  by 
five  rosettes  of  buccal  pores,  and  separated  by  five  prominent  lobes,  oral  aperture  regular, 
pentagonal,  with  equal  sides  and  a  prominent  angle  anteriorly.  Vent  small,  situated  in  a 
deep  groove  with  perpendicular  walls  and  well-defined  outline,  extending  nearly  half  way 
up  the  dorsal  surface  of  the  single  inter-ambulacrum,  ambulacra  narrowly  lanceolate,  and 
subpetaloidal ;  the  anterior  and  posterior  pairs,  especially  the  latter,  long  and  flexuous. 
The  pores  which  compose  the  zones  are  sometimes  imequal,  the  .external  series  being 
more  or  less  elongated  in  a  transverse  direction ;  apical  disc  small,  excentral,  and 
composed  of  four  perforated,  and  one  imperforate  genital  plates,  the  right  antero-lateral 
supporting  the  madreporiform  body,  which  extends  into  the  middle  of  the  disc  and  forms 
a  prominence  there;  the  five  ocular  plates  are  small  and  angled  into  the  summits  of 
lanceolate  ambulacra.  The  tubercles  are  very  small  and  set  closely  together  on  the 
upper  surface  (PL  LVI,  fig.  1/),  and  larger  on  the  under  surface  (PL  LVl,  fig.  3  _^)  ; 
they  are  all  encircled  by  areal  depressions  and  separated  by  minute  granules. 

This  group  was  separated  by  M.  A.  d'Orbigny  from  Echinobrissus  in  consequence  of  the 
following  characters,  which  he  observed  to  be  constant  in  all  the  species  : — The  large  central 
polypiform  madreporiform  body;  the  mouth-opening  surrounded  by  five  rosettes  of 
pores,  alternating  with  five  well-developed  buccal  lobes;  and  the  anal  sinus  circum- 
scribed and  contracted. 

The  species  are  all  special  to  the  Cretaceous  formations.  M.  d'Orbigny  described 
and  figured  six  from  the  Neocomian  and  two  from  the  Albian  stages,  and  I  now  add 
another  form  from  the  Neocomian  of  the  Isle  of  Wiatht. 


PROM  THE  LOWER  GREENSAND.  247 


Clypeopygus  Fittoni,  Wrigld,  nov.  sp.   PI.  LVI,  fig.  1 — 3. 

Test  oblong,  upper  surface  depressed,  highest  posteriorly ;  under  surface  concave ; 
ambulacra  narrow,  lanceolate  ;  poriferous  zones  subpetaloidal  above  and  narrowly  biserial 
on  the  sides  and  base ;  apical  disc  nearly  central ;  vent-opening  at  the  end  of  a  narrow 
sinus  with  vertical  walls  ;  mouth-opening  at  the  junction  of  the  anterior  with  the  middle 
third,  peristome  surrounded  by  five  prominent  lobes  and  five  pairs  of  subpetaloidal 
pores,  forming  together  a  well-marked  rosette. 

Dimensions. — No.  1,  length  I^^q- inches,  breadth  1  inch;  No.  2,  length  1-^- inches, 
breadth  \-^  inch. 

DescrijJtion. — The  outline  of  the  test  is  oblong,  with  the  sides  slightly  compressed ; 
the  upper  surface  is  convex,  flattened  at  the  anterior  half,  and  gradually  elevated  towards 
the  posterior  third,  which  is  the  highest  part  of  the  test  (PI.  LVI,  fig.  1  (/,  fig.  3  e) ;  from 
this  point  it  bends  abruptly  down  to  the  posterior  border;  Mr.  Bones'  capital  figures 
in  PI.  LVI  make  this  character  of  the  test  far  more  intelligible  than  the  most  laboured 
description  could  effect. 

The  ambulacral  areas  are  narrowly  lanceolate,  the  antero-  and  postero-lateral  pairs 
are  long  and  flexuous,  and  the  single  area  is  short  and  straight ;  the  poriferous  zones 
(fig.  3  /)  are  slightly  subpetaloidal  on  the  dorsal  surface  (fig.  1  b,  fig.  3  b),  and  closely 
biserial  on  the  sides  and  at  the  base  (fig.  1  d,  e,  fig.  1  c,  fig.  3  c) ;  as  they  approach  the 
peristome,  they  expand  and  form  five  petaloidal  expansions  around  the  mouth,  which  are 
separated  from  each  other  by  the  five  lobes  that  surround  the  oral  opening  (fig.  3  c). 

The  inter-ambulacral  areas  are  largely  developed ;  the  antero-lateral  are  the  narrowest, 
the  postero-lateral  the  widest,  and  the  single  area  of  intermediate  width ;  they  are  built  of 
large  plates  bent  in  the  middle,  having  their  surface  closely  covered  with  small  scrobicu- 
lated  tubercles  arranged  in  horizontal  rows ;  fig.  1  /  shows  three  of  these  jjlates  and  a 
corresponding  portion  of  the  ambulacral  area  with  the  poriferous  zones,  magnified  six 
diameters.  The  tubercles  at  the  base  are  larger  and  wider  apart  than  those  on  the 
upper  surface,  as  shown  in  fig.  3  ff,  where  a  portion  of  the  base  is  magnified  three 
diameters ;  the  boss,  area,  and  imperforate  tubercle  are  well  seen  in  this  drawing. 

The  vent  opens  at  the  end  of  a  deep  sulcus  near  the  middle  of  the  dorsal  portion  of 
the  single  inter-ambulacrum-,  see  figs.  1  b,  c,  fig.  ^  b,d;  the  walls  of  the  sulcus  are 
abruptly  perpendicular  (fig.  3  b,  d,  c),  and  the  oval  periprocte  is  seen  at  the  upper  portion 
thereof  (fig.  1  e,  fig.  3  b,  d) ;  the  single  inter-ambulacrum  exceeds  in  height  all  the  others, 
for  its  upper  surface  is  elevated  (fig.  1  a),  and  forms  the  vertex  of  the  test,  whilst  its 
under  surface  is  curved  downwards  and  forms  a  marked  prominence  in  the  base 
(fig.  1  d,  e,  fig.  3  a,  e)  -.  I  have  not  seen  the  apical  disc  well  shown  in  any  specimens. 


248  ECHIA^OBRISSUS 

The  base  is  concave,  and  the  mouth-opening  occupies  a  deep  depression  at  the 
junction  of  the  anterior  with  the  middle  third  of  the  base  (fig.  3  c) ;  the  development  of 
the  five  oral  lobes,  and  the  five  alternating,  petaloidal  rosettes  impart  a  remarkable 
generic  character  to  the  only  specimen  in  which  this  portion  of  the  anatomy  of  the  test  is 
satisfactorily  exposed.  I  have  given  a  figure  of  this  structure,  as  all  the  other  specimens 
have  the  base  covered  more  or  less  with  the  coarse  grains  of  the  matrix. 

Affinities  and  Differences. — This  species  resembles  Clypeopyrjus  Cerceleti,^Oxh.,\\\  all 
the  chief  points  of  its  anatomy,  but  differs  in  the  following  particulars  : — C.  Fiifonihas 
the  test  more  oblong  or  subquadrate,  and  not  enlarged  posteiiorly ;  the  single  inter- 
ambulacrum  is  more  developed,  rises  higher  on  the  upper  surface,  and  curves  lower 
on  the  under  surface  than  in  d'Orbigny's  figure  of  C.  CerceMi. 

Locality  and  Stratic/raphical  Position. — This  rare  Urchin  was  collected  from  the 
Lower  Greensand  of  Shanklin,  Isle  of  Wight,  by  the  Rev.  T.  Wiltshire,  F.G.S.,  and 
myself.  I  have  dedicated  the  species  to  the  memory  of  my  old  friend  Dr.  Fitton, 
F.R.S.,  whose  admirable  monograph  on  the  Lower  Greensand  of  the  Isle  of  Wight  will 
long  remain  a  text-book  to  the  explorers  of  this  classical  geological  region. 


Genus — Echinobrissus,  Sreynius,  1732. 

KucLEOLiTES,     Lamarcl',  1801. 

—  Goldfuss,  1S2G. 

—  Agassi:,  1837. 
Echinobrissus,  d'Orbiymj,  1855. 

—  Desor,  1857. 

—  Cot  fern,  1858. 

—  J)e  Loriol,  1868. 

This  natural  group  is  composed  of  small  Urchins  which  have  an  oval,  oblong,  subquadrate, 
or  subcircular  form,  more  or  less  convex  on  the  upper  surface,  and  slightly  concave  at 
the  base  ;  the  test  is  obtusely  rounded  anteriorly,  more  or  less  produced,  truncated,  or 
lobed  posteriorly,  and  in  general  is  nari'ower  at  the  anterior  than  the  posterior  third ;  the 
vent  opens  into  an  anal  sulcus  which  in  one  group  extends  from  the  apical  disc  to  the 
posterior  border,  and  in  another  is  limited  to  the  lower  third  of  the  inter-ambulacrum ; 
the  periprocte  was  closed  by  a  series  of  small  anal  plates  usually  absent  in  fossil  forms, 
but  preserved  in  the  only  living  descendant  of  the  genus. 

The  base  is  more  or  less  concave ;  the  mouth-opening  is  small,  pentagonal, 
excentral,  and  lodged  in  an  excentral  depression ;  in  one  group  the  peristome  forms 
a    regular   pentagon ;    in    another    group    it    is    directed    obliquely    across   the    test. 


FROM  THE  UPPER  GREEN  SAND.  24^ 

D'Orbigny  has  separated  the  latter  into  a  distinct  genus  under  the  name  Trematopypis, 
all  of  which  are  special  to  the  Cretaceous  Rocks ;  and  they  form  a  convenient  section  of 
the  genus,  although  the  characters  on  which  the  separation  is  based  are,  from  my  point  of 
view,  too  slight  and  evanescent  to  form  a  stable  generic  basis.  The  apical  disc  is  small, 
quadrate,  and  compact ;  it  is  composed  of  four  perforated  and  one  imperforate  genital  plute, 
the  right  antero-lateral,  supports  the  madreporiform  body ;  the  five  oculars  are  very  small 
and  triangular,  and  are  wedged  in  between  the  genitals  and  apices  of  the  lanceolate 
ambulacra. 

The  tubercles  are  small,  with  perforated  summits  and  depressed  areas,  and  the 
surface  of  the  plates  is  covered  with  microscopic  granulations. 

The  genus  Echinobrissus  was  established  by  Breynius  in  1732  in  his  important 
memoir  '  De  Echinis  et  Echinitis,'  and  of  which  I  have  given  a  translation  at  p.  193. 

Klein,  who  published  only  two  years  afterwards,  did  not,  unfortunately,  preserve  the 
well-defined  genera  proposed  on  such  good  characters  by  his  learned  contemporary ; 
and  Leske,  his  commentator,  in  1778  placed  the  Ecldnohrissus  of  Breynius  under  the 
Spataiiffus  of  Klein.  When  Lamarck  in  1801  proposed  the  genus  Nudeolites  in  the 
first  edition  of  his  great  work,  he  was  not  aware  that  the  same  group  of  Urchins  had 
been  well  figured  and  accurately  diagnosed  si.xty-nine  years  before  by  Breynius ;  but  in 
the  second  edition  of  '  Animaux  sans  Vertebres '  a  reference  was  made  to  this  work  for 
figures  of  the  species.  The  late  Professor  Agassiz  in  dismembering  Lamarck's  Nudeolites 
unfortunately  did  not  restore  Breynius'  genus,  although,  as  a  rule,  Agassiz  adhered  to  the 
genera  of  the  older  naturalists.  To  the  late  Professor  A.  d'Orbigny  the  honour  is  due 
of  vindicating  the  claims  of  Breynius's  work,  and  which  all  subsequent  Echinologists, 
Desor,  Cotteau,  and  De  Loriol,  have  rigidly  observed. 


Echinobrissus  lacunosus,  GoWfuss}  1S29. 

KucLEOLiTEs  LACUNOsus,  GolJfuss.     Petref.  Germanise,  pi.  .\liii,  fig.  8,  p.  141,  1 829. 

—  —  Besmoulins.     fitiides  sur  les  Echinides,  p.  360,  1837. 

—  —  Morris.     Cat.  of  Brit.  Foss.,  p.  55,  1843. 

—  —  Agassis  et  Desor.     Cat.  raison.,  p.  97,  1847. 

—  —  Forbes.     Mem.  Geol.  Survey,  Decade  i,  p.  8,  1849. 
Echinobrissus    —             d'Orbigny.   Pal.  Franc.  Ter.Cret.,  pi.  958,  figs.  7— 10, 1855. 

Bia(jnosis. — Test  ovate,  obtuse  anteriorly,  subquadrate  and  subtruncate  posteriorly, 
sides  subcompressed  ;  upper  surface  convex,  vertex  subcentral  or  supra-anal ;  ambulacra 
narrowly  lanceolate;    anal  sulcus  deep,  short,  oblong,  and  abruptly  declined;    inter- 
'  No  specimen  has  been  found  hitherto  sufficiently  perfect  for  the  purpose  of  illustration. 

32 


250  ECHINOBRISSUS 

ambulacrum  subdepressed,  recurved ;  base  concave ;  mouth-opening  surrounded  by  five 

short  petaloid  poriferous  zones. 

Dimensions. — Length  seven  tenths  of  an  inch ;  breadth  half  an  inch. 

Description. — The  test  of  this  species  is  obtusely  rounded  before,  and  subquadrate 

and  truncated  behind ;  the  sides  are  shghtly  compressed,  and  the  posterior  third  is  the 

widest  part  of  the  ambitus.     The  upper  surface  is  convex  and  the  under  surface  concave, 

and  inclined  upwards  towards  the  posterior  border. 

The  ambulacral  areas  are  narrowly  lanceolate,  and  the  dorsal  poriferous  zones  slightly 

subpetaloidal  on  the  sides  and  base  ;  the  pores  are  scarcely  visible  on  the  upper  surface, 

but  around  the  mouth  they  form  a  five-rayed  star  of  short  petaloidal  pores,  with  five  oral 

lobes  between  them,  as  in  Cli/peopi/(/us. 

The  apical  disc  is  small  and  excentral;  four  of  the  ovarial  plates  are  perforated. 
The  surface  is  covered  with  scrobiculated  tubercles.  The  mouth  is  situated  at  the 
jimctiou  of  the  anterior  with  the  middle  third,  and  is  surrounded  with  the  short  rosette 
of  pores  already  described ;  the  base  is  concave  between  the  sides,  and  curves  upwards 
towards  the  anterior  and  posterior  borders,  so  that  the  borders  of  the  postero-lateral  inter- 
ambulacra  are  convex  and  prominent  at  the  sides  and  base,  and  impart  to  this  Urchin  one 
of  its  best  diagnostic  characters.  The  anal  sulcus  is  short,  deep,  oblong,  and  abruptly 
declined,  and  occupies  the  region  above  the  posterior  border  of  the  inter-ambulacrum ; 
the  vent  opens  at  the  extreme  end  of  the  sulcus  above  the  middle  of  the  test. 

Affinities  and  Differences. — This  Urchin  was  well  figured  by  Goldfuss,  and  much 
resemljles  Echinohrissiis  similis,  d'Orbigny,  which  appears  to  be  a  large  variety  of 
JS.  lacunosus.  It  resembles  E.  Boberti,  Gras,  from  the  Upper  Neocomian,  but  is 
distinguished  from  that  form  by  the  following  characters :  the  anal  sulcus  is  lower, 
narrower,  and  nearer  the  border ;  the  sides  are  less  inflated  and  more  compressed ;  and 
the  base  curves  more  upwards  posteriorly. 

Localitij  and  8traii(/raphical  Position.  —  This  Urchin  has  been  long  collected  in 
the  Upper  Greensand  at  Longleat,  Wilts,  and  from  the  Chloritic  Marl  at  Chardstock; 
the  type-specimen  was  obtained  from  the  Chalk-marl  near  Essen  on  the  Ruhr, 
Westphalia. 


EcHiNOBRissus  MoRRisii,  Forbcs,  1849. 

Cassidulus  LAPis-CANCRi,  Morris.     Cat.  Brit.  Foss.,  p.  49,  1843. 
NucLEOLiTES  MoKEisii,       Forbes.     Mem.  Geol.  Surv.,  decade  i,  p.  8,  1849. 

—  —  Morris.     Cat.  Brit.  Foss.,  2  ed.,  p.  84,  1854. 

EcHiNOBEissus     —  d'Orbigny.     Pal.  Frau9.  Ter.  Cretaces,  pi.  959,  1854. 

Diagnosis. — Test   oblong,  anterior  and   posterior   borders  obtusely  rounded;    sides 


PROM   THE   UPPER   GREENSAND.  251 

compressed,  dorsal  surface  convex ;  ambulacra  lanceolate,  subpetaloidal ;  apical  disc 
excentral  and  forwards  ;  vertex  central ;  anal  sulcus  short,  deep,  and  subtriangular ;  base 
concave  ;  mouth-opening  pentagonal,  slightly  excentral,  and  forwards. 

dimensions. — Antero-posterior  diameter  half  an  inch  ;  height  three  tentlis  of  an  inch. 

Description.- — -The  test  is  oval  and  depressed,  obtusely  rounded  before,  a  little 
angular,  subrostrated,  and  sloped  out  behind,  and  the  greatest  diameter  is  at  the  pos- 
terior third.  The  upper  surface  is  convex  ;  the  longitudinal  profile  shows  it  to  be  rounded 
and  depressed  at  both  extremities,  with  a  slight  excentral  elevation  nearer  the  anterior 
than  the  posterior  border.  The  ambulacra  are  long,  lanceolate,  and  subpetaloidal  on  the 
dorsum,  narrower  at  the  ambitus,  and  enlarged  in  the  base ;  the  poriferous  zones  have  the 
pores  unequal,  and  a  little  apart  above  where  they  form  the  petals ;  they  are  close  together 
and  microscopic  at  the  ambitus,  and  are  larger  and  more  numerous  near  the  mouth,  where 
they  form  a  pentagonal  star  around  the  peristome.  The  anal  sulcus  occupies  the  lower 
fourth  of  the  single  inter-ambulacrum ;  it  is  short,  deep,  and  triangular,  and  its  two 
lateral  walls  form  prominent  carinaj,  the  sulcus  making  an  excavation  in  the  posterior 
border ;  the  vent  is  oval  and  opens  at  the  summit  of  the  valley. 

The  apical  disc  is  small,  quadrate,  with  four  perforated  genital  pores  ;  it  is  slightly 
excentral  and  placed  a  little  forwards,  and  forms  the  vertex  of  the  test. 

The  base  is  very  concave,  always  near  the  mouth,  and  greatly  undulated  at  the  sides, 
the  single  inter-ambulacrum  being  slightly  subrostrated  and  recurved. 

The  mouth-opening  is  excentral,  the  peristome  pentagonal,  with  one  angle  directed 
forwards,  and  the  pores  increase  in  size  and  number  in  the  ten  zones  around  this 
aperture. 

The  scrobiculated  tubercles  closely  cover  all  the  upper  surface ;  beneath  they  are  larger 
and  not  so  numerous. 

Affinities  and  Differences. — This  species,  which  is  very  rare  in  England,  was  said  by 
the  late  Professor  A.  d'Orbigny  to  resemble  E.  Bour(juigncdi,  but  to  be  distinguished 
from  it  by  having  the  test  much  more  depressed,  subrostrated  behind,  compressed  at  the 
sides,  humped  at  the  vertex,  and  more  concave  and  undidated  on  the  under  surface. 

Locality  and  Stratiyraphical  Position. — According  to  the  late  Professor  Porbes,  who 
first  separated  the  species  from  E.  lacunosus,  and  gave  only  an  imperfect  diagnosis  without 
any  figure  of  the  same,  this  Urchin  is  found  in  the  Upper  Greensand  of  Warminster  and 
Blackdown,  and  the  type  was  detected  in  Professor  Pennant's  collection.  On  the  Continent 
it  was  collected  by  the  late  Vicomte  d'Archiac  from  "  I'Etage  Cenomanien"  at  Brunswick. 
Unfortunately  the  figure  of  this  species  was  not  drawn  by  my  late  lamented  friend 
Mr.  Bone,  as  he  was  waiting  to  procure  a  good  specimen  to  draw,  and  had  not  obtained 
one  when  it  was  required. 


TREMATOPYGUS 


Genus — Trematopygus,  A.  d'Orhigny,  1855. 

NucLEOLiTES  (pars),     Agassiz. 
EcHixoBBissus  (pars),  Desor. 
Phvllobrissus  (pars),  Cotteau. 
—  (pars).  Be  Loriol. 


Form  of  tlie  test  ovate  or  oblong,  a  little  contracted  and  rounded  before,  and  more  or 
less  enlarged  behind. 

Upper  surface  convex,  ambitus  inflated,  posterior  inter-ambulacrum  slightly  ros- 
trated. 

Apical  disc  quadrate,  excentral,  and  nearer  the  anterior  border,  composed  of  four 
perforate  ovarial  and  one  single  imperforate  plates ;  the  madreporiform  body  covers  the 
genital  elements  and  forms  a  prominence  in  the  centre  of  the  disc ;  the  five  ocular  plates 
are  very  small  and  closely  united  to  the  genitals. 

The  ambulacra  are  long,  lanceolate,  and  well  defined  throughout ;  the  poriferous 
zones  are  subpetaloidal  on  the  upper  surface ;  the  outer  rows  of  the  dorsal  pores  are 
elongated  transversely  at  the  ambitus  and  base,  they  are  equal,  biserial,  and  microscopic, 
and  around  the  peristome  a  few  supplementary  pairs  are  present,  which  are  larger  and 
more  conspicuous  than  the  others. 

The  inter-ambulacra  are  built  of  large  plates  bent  in  the  middle,  having  their  surface 
covered  with  two  or  three  irregular  rows  of  tubercles,  which  are  perforated,  raised  on 
mammelons,  and  encircled  by  depressed  areas  having  circles  of  granules  around  them, 
and  the  inter-tubercular  surface  is  covered  with  a  fine  granulation. 

The  anal  sulcus  is  large,  shallow,  and  limited  to  the  posterior  border ;  the  vent  is 
large,  oval,  or  pyriform,  and  opens  near  the  surface. 

The  base  is  flat  or  slightly  concave  towards  the  middle ;  the  mouth-opening  is 
irregularly  pentagonal,  compressed  obliquely  from  left  to  right,  and  from  above  down- 
wards. 

Treniatoj)ijgus  is  only  a  sectional  group  of  the  genus  EchinobrissKs,  characterised  by 
an  oblique  compressed  peristome,  and  by  the  large  elongated  vent  placed  in  a  marginal 
shallow  sulcus. 


FROM  THE  LOWER  GREENSAND.  353 


Trematopygus  Faringdonensis,  Wriffht,  1871.     PI.  LVII,  fig.  1  a — h. 

Trematopygus  Faeixgdonensis,  Wright.     In  Phillips'  Geology  of  Oxford,  p.  -134, 

1871. 

Diagnosis. — Test  gibbous,  oval,  much  inflated  at  the  sides  and  base,  narrow  in  the 
anterior,  and  enlarged  in  the  posterior  third.  Apical  disc  and  vertex  excentral  and  for- 
wards ;  ambulacra  lanceolate,  dorsal  pores  snbpetaloid,  and  sulcus  excavated  out  of  the 
posterior  border ;  vent  pyriform,  large;  base  concave,  sides  undulated  by  the  inflation  of 
the  inter-ambulacra ;  mouth-opening  large  and  oblique,  and  situated  at  the  junction  of 
the  anterior  with  the  middle  third. 

Dimensions. — a.  Length  one  inch  and  three  tenths  ;  height  seven  tenths  of  an  inch  ; 
lireadth  one  inch  and  two  tenths,  h.  Length  one  inch  and  five  tenths ;  height  seven 
tenths  ;  breadth  one  inch  and  three  tenths. 

Description. — The  test  of  this  rare  Urchin  has  an  oval  outline,  is  a  little  narrower 
before  than  behind,  and  is  much  inflated  at  the  sides  and  base.  The  upper  surface  is 
convex  with  the  vertex  excentral  and  forwards,  fig.  1  a  and  b. 

The  ambulacra  are  long,  lanceolate,  unequal,  petaloid ;  the  posterior  pair  are  much 
longer  than  the  others,  and  the  single  area  is  the  shortest  and  narrowest ;  at  the  under 
surface  the  ambulacra  form  depressions,  and  the  inter-ambulacra  elevations,  so  that  the 
base  is  undulated  at  the  sides  and  concave  in  the  middle,  fig.  1  c. 

The  poriferous  zones  are  well  developed  at  the  upper  surface  and  the  external  rows 
are  slightly  elongated,  fig.  \  h ;  at  the  ambitus  and  base  the  pores  are  small  and  closely 
biserial,  and  become  larger  and  more  conspicuous  around  the  peristome,  fig.  1  c. 

The  apical  disc  is  small  and  quadrate,  fig.  1  a,  h ;  the  four  genital  plates  are  perfo- 
rated, and  the  anterior  pair  set  closer  together  than  the  posterior  pair ;  the  madreporiform 
body  occupies  the  middle  of  the  disc  and  forms  a  prominent  button  there.  The  ocular 
plates  are  very  small  and  closely  united  to  the  other  discal  elements,  see  fig.  1/,  where  the 
disc  is  shown  magnified  six  diameters. 

The  periprocte  is  pyriform  or  oval,  and  acuminated  at  the  upper  extremity,  fig.  1 
a,  b,  and  e;  it  is  quite  supra-marginal ;  the  anal  sulcus  makes  a  deep  indentation  in  the 
posterior  border,  fig.  1  b,  d,  e,  and  from  its  sides  two  carinas  proceed  towards  the  base, 
fig.  \e. 

The  tubercles  are  prominent  and  perforated,  and  raised  on  bosses  surrounded  by 
depressed  areas,  the  margins  of  which  are  encircled  by  granules,  and  all  the  inter- 
tubercular  surface  is  covered  with  a  well-developed  granulation,  fig.  Iff;  at  the  base 
the  tubercles  are  larger  and  more  spaced  out,  the  raammelons  are  larger,  and  the  granules 
surrounding  the  areas  more  developed,  fig.  1  h.     In  fig.  1  y  an  arabulacral  area  with  the 


I 
254  CARATOMUS 

poriferous  zones  together  Avith  a  portion  of  inter-ambulacra  is  shown,  consisting  of 
three  plates  magnified  six  diameters ;  the  arrangement  of  the  tubercles  is  most  accurately 
given,  and  their  relative  size  and  structure  well  shown  in  this  drawing. 

Afinities  and  Differences. — This  species  resembles  very  much  Trematopygus  C'amjrl- 
cheanus,  d'Orbigny.  Our  Urchin  is  larger  and  more  gibbous,  and  the  anal  sulcus  wider 
and  more  developed ;  the  base  likewise  is  more  undulated,  from  the  inflation  of  the  basal 
portions  of  the  inter-ambulacra ;  and  the  arrangement  of  rows  of  granules  above  the  pores 
in  the  poriferous  zones,  '  Pal.  Fran^aise,'  pi.  950,  fig.  0,  is  absent  in  T.  Farinc/donensis. 
In  the  absence  of  specimens  with  which  to  compare  these  nearly  allied  forms,  it  is 
impossible  to  decide  whether  they  are  specifically  distinct  or  only  varieties  of  T.  Olfersii. 

Locality  and StratigrajMcal Position. — I  have  collected  this  Urchin  only  in  the  Sponge- 
gravel  beds  of  Lower  Greensand  at  Coxwell,  near  Faringdon,  Berks.  The  fine  specimen, 
fig.  1  a,  was  obtained  from  this  locality,  and  presented  to  me  by  my  old  esteemed  friend 
Thomas  Davidson,  Esq.,  F.R.S.  I  am  likewise  indebted  to  E.  C.  Davy,  Esq.,  F.G.S., 
Wantage,  for  several  specimens  more  or  less  perfect  to  complete  my  description  of 
the  anatomy  of  the  test  of  this  very  rare  form.  It  is  worthy  of  note  that  the  group  to 
which  I  refer  the  species  all  come  from  beds  appertaining  to  the  Middle  Neocomian, 
"Etaye  Neocomien  vioyen,"  a  fact  of  importance  helping  to  determine  the  age  of  the 
Sponge-gravel  beds  of  Berkshire. 


Genus — Caratomus,  Ayassiz,  1840. 

Small  Urchins  Avith  an  ovoid  or  circular  test  rounded  before  and  often  rostrated 
behind ;  the  sides  are  thick  and  inflated,  the  upper  surface  is  convex,  and  the  apical  disc 
excentral  and  forwards ;  the  base  is  convex  with  a  slight  depression  arftuud  the  mouth- 
opening,  which  has  neither  lobes  nor  pores. 

The  vent  is  infra-marginal  and  not  visible  from  the  upper  surface,  it  is  transversely 
oblong  or  triangular,  and  situated  in  several  species  in  a  rostrated  development  of  the 
single  inter-ambulacrum. 

The  ambulacra  are  short  and  subpetaloid,  and  the  zones  are  formed  of  simple,  equal, 
non-conjugate  pores,  disposed  in  pairs,which  are  closely  approximated  at  the  summit,  apart 
in  the  middle  of  the  zone,  and  approximated  at  the  ambitus,  PI.  LVII,  fig.  2  h,  c ;  at 
the  base  they  are  feebly  indicated  by  lines  which  converge  around  the  mouth-opening. 

The  tubercles,  which  are  large  for  so  small  a  test,  are  scrobiculated,  those  at  the  base 
are  the  largest,  and  the  sm-face  of  the  plates  likewise  is  covered  with  minute  granu- 
lations. 


FROM  TPIE  UPPER  GREENSAND.  255 

The  apical  disc  is  nearly  central,  with  four  perforated  ovarials  and  five  small  oculars, 
the  spongy  body  extending  into  the  middle  of  the  disc. 

The  mouth-opening  is  nearly  central,  always  obliquely  elongated. 

This  genus  belongs  essentially  to  the  Cretaceous  formations.  The  Upper  Greensand, 
Craie  Chloritee,  or  Etage  Cenomanien,  has  yielded  C.  trirjonopi/ffus,  faba,  rostratus,  and 
orbicularis ;  of  these  the  first  three  are  found  both  in  the  Anglo-Parisian  and  in  the 
Pyrenean  basins,,  and  the  last  up  to  the  present  time  only  in  the  Anglo-Parisian  basin. 

In  the  White  Chalk,  or  I'Etage  Senonien  are  four  species — C.  avcllanus,  sidcato-radiatus, 
tniiicatus,  ?iw^  peltiformis,  all  of  whicli  are  found  in  the  Anglo-Parisian  basin. 

The  only  specimen  discovered  in  England  is  C.  rostratus. 


Caratomus  rostratus,  Ayassiz,  1840,  PI.  LVII,  fig.  2  a — e. 

Caratomus  kosteatus,  Agassiz.     Catalogus  Syst.  Ectyp.,  p.  7,  1840. 

—  —  Besor.     Monog.  des  Galerites,  p.  38,  pi.  5,  figs.  1 — 4,  1842. 

—  —  Morris.     Cat.  of  Brit.  Foss.,  p.  49,  1843. 

—  —  Agassiz  et  Desor.     Cat.  Rais.,  p.  93,  Modele  No.  81,  1847. 

—  —  d'Orbigny.     Prodrom.,  t.  ii,  p.  178,  Stage  20e,  1847. 

—  —  Forbes.     In  Morris'  Cat.  of  Brit.  Foss.,  p.  73,  1854. 

—  —  (/'Or%Ky.  Pal.  Fran9aise,  Ter.  Cre'taces,  pl.941,p.  367, 1855, 

Diagnosis. — Test  thick,  depressed,  round,  inclining  to  oblong,  obtusely  round  before, 
and  prolonged  into  a  rostrum  behind ;  apical  disc  slightly  excentral ;  base  convex, 
pulvinated,  depressed  near  the,  mouth,  wdiich  is  small,  oblique,  and  excentral;  vent 
triangular,  infra-rostral  at  the  lower  third  of  the  height ;  ambulacra  narrow  and  obscured 
by  large  scrobiculated  tubercles. 

Dimensions. — Antero-posterior  diameter  four  tenths  of  an  inch  ;  breadth  three  tenths 
of  an  inch  ;  height  two  tenths  of  an  inch. 

Description. — This  little  Urchin  was  first  figured  and  described  by  M.  Desor  in  his 
beautiful  Monograph  on  the  Galerites  and  has  since  been  figured  by  d'Orbigny  in  the 
'  Paleontologie  Eran9aise.'  The  shell  is  thick  and  depressed,  longer  than  wide,  very  obtuse 
anteriorly,  and  ending  in  a  prolonged  rostrum  posteriorly,  which  gives  it  a  pyriform 
aspect. 

The  ambulacra  are  narrow  and  scarcely  visible,  being  obscured  by  large  scrobiculated 
tubercles ;  in  order  to  expose  the  poriferous  zones  it  is  often  necessary  to  treat  the 
test  with  some  dilute  acid.  I  have  never  been  fortunate  enough  to  obtain  so  good  a 
specimen  as  the  one  which  my  late  esteemed  friend  Mr.  Bone  procured  for  his  beautiful 


256  ECHIXOLAMPIDtE. 

drawings  of  tins  species,  and  of  which  he  has  given  details  all  magnified  six  diameters.  The 
ambulacra  are  narrow  and  subpetaloid  and  the  pores  in  the  zones  are  small,  equal,  and 
non-conjugate.  The  surface  of  tlie  test  is  covered  with  scrobiculated  tubercles,  which  are 
large  in  proportion  to  the  size  of  the  shell ;  these  Avith  the  thickness  of  the  test  serve  to 
obscure  the  details  of  its  structure. 

The  apical  disc,  which  is  likewise  the  vertex,  is  placed  a  little  before  the  centre,  and  is 
composed  of  four  perforated  genital  and  five  ocular  plates,  and  the  spongy  body  projects 
towards  the  middle  of  the  disc. 

The  large  triangular  vent  is  situated  at  the  under  side  of  the  projecting  rostrum,  fig.  2  c\ 
d,  e,  and  is  so  completely  infra-marginal  that  the  aperture  cannot  be  seen  from  the  upper 
surface.  The  great  development  of  the  intra-ambulacrum  which  produces  the  rostrum 
fomis  one  of  the  most  marked  characters  of  this  species,  fig.  2  c,  and  serves  to  distin- 
guish it  from  the  congeners. 

The  base  is  convex  and  pulvinate  ;  it  is  a  little  depressed  near  the  middle,  where  the 
oblique  mouth-opening  is  situated,  fig.  2  c;  the  lines  of  zone-pores  are  here  visible,  and 
the  scrobiculated  tuljercles  are  even  larger  than  on  the  upper  surface. 

Affinities  mid  Dijfcrences. — This  species  resembles  C.  trirjonopygus,  but  is  distinguished 
from  it  by  its  long  recurved  rostrum,  fig.  2  c.  The  shell  is  likewise  more  inflated  and  the 
base  more  convex. 

LocnUiij  and  Stratigrapliical  Position. — This  species  is  found  only  in  the  Upper 
Greensand  near  Warminster,  Wilts.  In  France  it  is  likewise  special  to  "  I'Etage  Ceno- 
manien,"  or  the  "  Craie  Chloritee,"  from  whence  it  has  been  collected  at  Havre, 
Seine-Infcriem'e,  at  Fourras,  Charente-Inferieure,  and  at  Vaches-Noires,  Calvados. 


Family  10 — Echinolampid^,  Wright,  1856. 

Test  thin,  oval,  oblong,  elevated,  or  subdiscoidal ;  ambulacral  areas  large,  petaloidal  -, 
poriferous  zones  wide,  pores  distant,  united  by  sutures,  and  extending  nearly  to  the 
margin. 

Mouth-opening  small,  subcentral ;  peristome  smTounded  by  five  prominent  lobes,  and 
always  by  a  well-developed  pentaphylloid  floscelle. 

Vent  oval  transversely  and  infra-marginal. 

Apical  disc  very  small,  excentral,  and  composed  of  four  perforated  genital  and  one 
imperforate  plate,  with  five  minute  oculars  wedged  into  the  circumference  of  the  disc. 

Plates  of  the  upper  surface  covered  with  several  rows  of  numerous  small,  closely  set 
tuljercles  encircled  bv  sunken  areolas. 

A  few  species  are  now  living  in  warm  seas  ;  the  greatest  number  are  extinct,  and 


FROM  THE  UPPER  GREENSAND.  257 

found  in  the  Oolitic,  Cretaceous,  and  Tertiary  rocks,  where  they  form  important  leading 
fossils  of  the  strata  which  they  characterise. 

I  include  the  following  genera  in  this  Family : 

EcHiNOLAMPAS,  Gray.  Echinanthus,  Breynius. 

Pygurus,  d'Orhigny.  Conoclypus,  Jyassiz. 

Faujasia,  d'Orbiffny.  Pygaulus,  Jgassiz. 


Genus — Pygurus,  tVOrbigny,  1S55. 

EcHiKANTHiTES,  Leske,  1778. 

Clypeasteu  (pars),  Lamarck,  1801. 
EcHiNOLAMPAS  (pars),  Agassiz,  1836. 

Pygurus  (pars),  Agassiz,  1840. 

—  cVOrhigny,  1855. 

—  Besor,  1858. 

—  Be  Loriol,  1873. 

The  genus  Pygurus,  as  now  limited,  is  composed  of  large,  discoidal,  or  clypeiform 
Urchins,  in  wliich  the  test  in  general  is  more  or  less  enlarged  at  the  sides,  and  rostrated 
posteriorly ;  its  upper  surface  is  usually  depressed,  and  rarely  elevated.  The  ambulacral 
areas  and  poriferous  zones  in  the  upper  surface  form  petaloidal  expansions,  which  have  an 
elegant  figure,  being  in  general  contracted  at  the  border,  enlarged  in  the  middle,  and 
attenuated  at  the  apex.  The  anterior  single  area  is  narrower  than  the  antero-  and 
postero-lateral  areas ;  the  summit  is  in  general  central,  or  slightly  cxcentral,  the  inclina- 
tion being  always  forwards.  The  base  is  concave  and  much  undulated,  the  wide  basal 
interambulacra  swell  into  prominent  cushions,  and  the  narrow  ambulacra  form  contracted 
valleys  between  them.  The  mouth-opening  is  pentagonal,  and  always  excentral ;  the 
peristome  is  surrounded  by  five  prominent  lobes,  with  which  five  expanded  ambulacral 
petals  alternate ;  in  the  poriferous  zones  near  the  mouth  the  pores  are  closely  crowded  in 
triple  oblique  ranks ;  these  perforated  petals  form  an  oral  rosette  or  a  penta-phylloid 
floscelle  of  considerable  dimensions  (PI.  LVIII,  fig.  1  c). 

The  vent  is  infra-marginal ;  it  is  in  general  oval,  and  surrounded  by  a  distinct  area, 
which  occupies  the  rostrated  portion  of  the  single  interambulacrum  ;  the  long  diameter  of 
the  opening  in  general  corresponds  with  the  longitudinal  axis  of  the  test,  although  it  is 
sometimes  transverse  (PI.  LVIII,  fig.  1  c). 

The  apical  disc  is  very  small,  and  occupies  the  summit ;  it  is  composed  of  two  pairs  of 

33 


258  PYGURUS. 

narrow,  perforated,  and  a  single  rudimentary  imperforate,  ovarial  plate ;  five  minute 
ocular  plates,  are  interposed  between  the  ovarials  (PI.  LVIII,  fig.  1  h). 

The  small  madreporiform  body  is  attached  to  the  surface  of  the  right  anterior  ovarial, 
and  forms  thereon  a  spongy  eminence,  which  extends  over  the  other  discal  elements. 

The  tubercles  are  very  small  on  the  upper  surface,  and  larger  at  the  base ;  they  are 
surrounded  by  sunken  areolas,  and  have  their  summits  perforated ;  the  intertubercular 
space  is  covered  with  close-set  miliary  granules  (PI.  LVIII,  fig.  1  ^). 

The  genus  Fygurus  first  appears  in  the  Lower  Oolites,  and  its  species  are  likewise 
found  in  the  Inferior  Oolite,  Puller's  Earth,  Great  Oolite,  Cornbrash,  Kelloway  Rock, 
Coralline,  and  Portland  Oolite. 

In  the  Cretaceous  formations  the  species  Fi/(/urus  rostraius,  P.  GiUieroni,  P. 
Buchii,  characterise  the  Lower  Neocomian  or  Valangian ;  Pygurus  Monfmolini  and  P. 
Salevcnsis  are  found  in  the  Middle  Neocomian ;  Pygurus  productus  comes  from  the 
Urgonian ;  Pygurus  Eicordeanus  from  the  Gault ;  Pygurus  Lampas  from  the  Upper 
Greensand  or  Cenomanian.  Of  the  eight  Cretaceous  species  one  is  found  in  the  English 
Upper  Greensand,  where  it  is  so  rare  that  I  know  only  of  two  specimens,  and  one  of 
these  is  preserved  in  the  British  Museum. 


Pygurus  Lampas,  Be  la  Beche,  1819,  PI.  LVIII,  figs.  \a — \h. 

Clypeaster  oviformis,  Lamarck.     Anim.  sans  Vert^bres,  t.  iii,  p.  15,  1816. 
EcHiNOLAMPAs  Lampas,  De  la  Beche.     Geol.  Trans.,  2nd  eer.,  p.  112,  t.  iii,  fig.  3,  1819. 
Pygduus  trilobus,  Agassiz.     Cat.  Syst.  Ecty.,  p.  5,  1840. 

—  —  Jffassh  and  Desor.     Cat.  rais.,  p.  103,  Modele  No.  39,  1847. 

—  —  d'Orbigny.     Prodrome,  t.  ii,  p.  178,  Etage  20,  1847. 

—  OVIFORMIS,       d'Orbigny.     Pal.  Fran9aise,  t.  91  9,  torn,  vii,  p.  311,  1855. 

—  Lampas,  Desor.     Synopsis  Echinides  foss.,  p.  311,  1858. 

Biagnosis. — Test  high,  very  convex  above  and  concave  beneath,  much  longer  than 
wide,  largely  rostrated,  and  abruptly  truncated  behind ;  ambulacra  lanceolate,  poriferous 
zones  subpetaloidal,  apical  disc  and  vertex  excentral ;  base  very  concave  and  much  undu- 
lated ;  mouth  excentral ;  peristome  surrounded  by  a  pentapetaloid  floscelle  of  complicated 
structure ;  interambulacrum  much  developed,  recurved,  and  truncated  ;  vent  transverse 
and  infra-marginal. 

Bimensions. — This  very  I'are  British  Urchin  was  first  noticed  by  my  old  esteemed  friend 
Sir  Henry  De  la  Beche,  E.R.S.,  who  collected  it  from  the  Upper  Greensand  near  Lyme 
Regis,  and  figured  it  in  the  '  Transactions  of  the  Geological  Society,'  depositing  the  specimen 


FROM  THE  UPPER  GREENSAND.  259 

in  the  British  Museum.  Sir  Heury  called  it  Lampas,  from  its  i-esemblance  to  an  ancient 
lamp  when  held  with  the  base  uppermost.  Lamarck,  1816,  described  a  Clypeaster  as  C. 
ovi/ormis,  from  the  South  Sea,  collected  by  Peron  and  le  Sueur,  and  referred  "  la  variete 
que  se  trouve  fossile  dans  les  vignes  aux  environs  du  Mans"  to  the  same  species.  Erom  the 
angular  character  which  the  posterior  half  of  the  test  exhibits  Agassiz  called  it  trilobus. 
D'Orbigny,  finding  that  Lamarck  had  noticed  the  fossil  species  from  Mans  as  a  variety  of 
C.  oviformis,  has  given  this  name  to  the  fossil,  which  is  quite  distinct  from  the  living 
form.  I  have,  therefore,  followed  my  friend  Professor  Desor,  and  retained  Sir  Henry 
De  la  Beche's  most  appropriate  name. 

The  test  is  oval  or  oblong,  obtusely  rounded  before,  hollowed  out  on  the  sides,  and 
prolonged  into  an  abruptly  truncated  rostrum  behind ;  it  is  very  convex,  and  inflated  on 
the  upper  surface,  its  profile  forming  a  regular  curve,  which  is  a  little  more  depressed 
behind  the  vertex  than  before  (fig.  1  a).  The  ambitus  is  very  angular  (fig.  1  a,  b)  in  its 
posterior  half,  and  the  two  lateral  and  one  posterior  lobe  gives  value  to  the  name  trilobus 
which  was  proposed  for  it.  The  single  inter-ambulacrum  is  much  prolonged,  and  on  it 
two  carinse  are  developed,  which  proceed  from  the  apical  disc  to  the  sides  of  the 
truncated  border  (fig.  1  b,  c),  and  impart  a  still  more  angular  appearance  to  the  test. 

The  ambulacra  are  largely  petaloid  on  the  upper  surface  (fig.  1  b).  They  are 
contracted  at  the  ambitus  (fig.  1  d,  e),  and  are  again  largely  developed  and  petaloidal  at 
the  base  (fig.  1  c). 

The  poriferous  zones  are  well  developed  and  visible  throughout  in  the  petaloidal 
portion  on  the  dorsum  ;  the  pores  in  the  external  row  are  elongated,  and  in  the  internal 
row  round  ;  at  the  ambitus  they  are  remote  and  microscopic,  and  in  the  base  they  again 
become  largely  petaloidal,  where  they  surround  the  mouth ;  the  petals  here  are  distin- 
guished hy  their  elegant  forms  and  complicated  structure ;  the  pores  are  increased  in 
number,  and  set  in  oblique  pairs  on  the  sides  of  the  petals,  and  in  the  centre  of  each  is  a 
longitudinal  enlargement  like  the  stem  of  a  leaf  (fig.  1  c).  This  remarkable  structure  is 
shown  magnified  two  diameters. 

The  large  plates  on  the  upper  surface  have  several  rows  of  small  tubercles,  which 
become  larger  and  less  numerous  at  the  base  (fig.  1  (/) ;  besides  these  a  fine  close-set 
granulation  covers  the  surface  of  all  the  plates. 

The  apical  disc  is  very  small,  so  that  the  lanceolate  ambulacra  meet  close  together  at 
the  vertex,  which  is  slightly  excentral ;  there  are  four  perforated  genital  plates,  with  a 
small  spongy  body  in  the  centre  (fig.  1  //). 

The  vent  is  large,  transversely  oval,  and  opens  near  the  border  of  the  infra-marginal 
portion  of  the  rostrum  (fig.  1  c). 

Affinities  and  Differences. — This  fine  Urchin  is  distinguished  from  its  congeners  by  its 
elevated  upper  surface,  angular  ambitus,  prolonged  rostrum  and  hollowed-out  sides,  by  its 
rostral  carinse,  and  the  remarkable  pentapetaloid  arrangement  of  the  pores  around  the 
peristome. 


260  SPATANGIDyE. 

Locality  and  Stratij^rapJdcal  Position. — It  was  collected  from  the  Upper  Greensand 
near  Lyme  Regis,  where  it  appears  to  be  very  rare,  as  I  have  seen  only  one 
other  English  example  in  addition  to  Sir  Henry  De  la  Beche's  gift  to  the  British 
Museum.  In  France  it  is  found  not  unfrequently  in  the  Micaceous  Sandstone,  I'etage 
Cenomanien  of  Mans,  Sarthe,  and  in  the  Gres  Calcarifere  (Cenomauien),  of  Fouras, 
Charente-Inferieure. 


Family  11. — CLYPEASTERiDiE,  WriffJit,  1856.     (Not  yet  found  in  British  Cretaceous 

strata.) 


Family  12. — Spatangid^,  d'Orbiyny,  1853. 

The  general  outline  of  the  urchins  of  this  family  is  oval,  oblong,  or  cordiform,  and 
they  satisfactorily  exhibit  the  bilateral  symmetry  of  the  Echinidse.  Tbe  mouth  is 
anterior,  bilabiate,  and  edentulous.  The  anal  opening  is  posterior  and  supramarginal, 
and  closed  by  a  complicated  series  of  small  periproctal  plates.  The  arabulacral  areas  are 
united  at  the  summit  of  the  test.  The  anterior  single  ambulacrum  has  a  different 
structure  from  the  antero-  and  postero-lateral  pau's,  and  is  lodged  in  a  depression 
of  the  test,  which  extends  to  the  anterior  border  and  forms  the  anteal  sulcus ;  the 
test  is  extremely  thin,  and  covered  with  small  perforated  tubercles,  which  support 
hair-like  spines ;  besides  these  there  are  some  larger  crenulated  and  perforated  tuljercles, 
which  support  large  spines.  There  are  two  or  four  genital  pores,  which  are  some- 
times placed  close  together,  but  in  other  genera  are  apart.  The  eye-plates  are  five 
in  number,  and  placed  in  a  pentagonal  form  at  the  apices  of  the  ambulacra  around 
the  genital  plates.  We  observe  on  the  surface  of  the  test  of  some  Spatangidse  certain 
delicate  lines  called  fascioles,  having  a  smoother  appearance  than  the  tubercular  sur- 
face of  the  test ;  they  are  furrows  which  are  strewed  with  microscopic  tubercles 
destined  to  carry  very  delicate  spines  which,  when  seeu  under  the  microscope,  appear 
to  have  a  structure  similar  to  the  Pedicellarise.  The  fascioles  have  a  different  dispo- 
sition in  each  genus,  and  afford  a  good  generic  character  in  giving  definitions  of  the 
same ;  when  the  fascicle  surrounds  the  ambulacral  petals  like  an  undulating  groove, 
as  in  Hemiaster,  Schizaster,  &c.,  it  is  said  to  be  peripetalous ;  when  it  surrounds  the 
single  ambulacrum,  as  in  Jmpkidetus,  it  is  internal ;  when  it  extends  along  the  sides,  as 
in  ScJiizaster,  it  is  lateral ;  when  it  encircles  the  circumference  of  the  test,  as  in 
Pericosmtis,  it  is  marginal;  when  it  is  limited  to  the  base  of  the  anal  opening  it  is 


IIEMIASTER.  261 

subanal.     We  find  sometimes  in  tlie  same  genus  more  fascioles  than  one;   thus  the 
subanal  and  peripetal  are  frequently  associated  together. 

This  family  contains  many  genera,  none  of  which  are  found  in  rocks  older  than  the 
Cretaceous  formations ;  the  species  increase  in  number  in  the  Tertiary  beds,  and  attain 
their  greatest  development  in  our  present  seas.  In  the  Cretaceous  rocks  we  find  the 
extinct  genera 

Hemiaster,  Desor.  Enallaster,  d'Orbipii/. 

Epiaster,  d' Orhigny.  '  Heteraster,  d'Ordigny. 

Micraster,  d'Orbi(/mj.  Echinospatagus,  Brepiitis. 

The  new  genus  Paleopneustes,  Al.  Agassiz,  proposed  for  a  species  brought  from 
Barbadoes  by  the  Hassler  expedition,  appears  to  fiumish  an  interesting  link  between  the 
EcHiNOCORiD^  and  SpATANGioiE.  In  its  general  form  it  resembles  Ecldnocorys 
vulgaris,  its  anteal  sulcus  is  rudimentary,  and  it  has  structural  affinities  with  the  anterior 
single  area  of  that  Urchin.  The  other  ambulacra  are  subpetaloidal ;  and  the  peristome 
bilabiate  with  well-developed  lips. 


Genus — Hemiaster,  Desor,  1847. 

Urchins  with  a  short,  elevated,  inflated,  or  cordiform  test.  The  ambulacral  summit 
in  general  excentral  and  posterior.  The  pairs  of  ambulacra  petaloidal,  unequal  in  length, 
and  lodged  in  depressions  of  the  surface ;  poriferous  zones  large  and  equal  in  the  same 
ambulacra,  the  pores  elongated  and  placed  close  together.  The  single  ambulacrum 
lodged  in  a  long,  shallow,  anteal  sulcus  ;  the  poriferous  zones  are  very  narrow  and  com- 
posed of  small  round  pores,  sparsely  disposed  in  oblique,  widely  separate,  simple  pairs. 

The  fasciole  single,  peripetalous,  and  circumscribing  the  ambulacra. 

The  apical  disc  small  and  compact,  four  perforated  genital  plates,  and  five  very  small 
oculars. 

Peristome  bilabiate,  very  excentral,  opening  at  the  anterior  fourth  part  of  the  base. 

Periprocte  opening  high  up  on  the  posterior  border,  which  is  in  general  flat,  and 
obliquely  truncated. 

Hemiaster  differs  from  Micraster  in  having  a  single  peripetalous  fasciole  and  no  anal 
fasciole ;  the  test  likewise  is  in  general  shorter,  more  inflated,  and  the  posterior  pair  of 
ambulacra  are  mucli  shorter  than  the  anterior  pair.  Hemiaster  differs  from  Periaster  in 
having  only  a  peripetalous  fasciole,  the  latter  having  both  peripetalous  and  lateral 
fascioles. 


262  HEMIASTER. 


Hemiaster  Morkisii,  Forbes,  1S54.     PI.  LXI,  fig.  a — k. 

Spatangus  pkunelia,  Mantell.     Geology  of  Sussex,  pi.  xvii,  figs.  22,  23, 

1822. 
Hemiaster         —  Besor.  (pars)     Cat.  raisonee,  p.  122,  1847. 

EcHiNOSPATANGUS  CORDIFOKMIS,  Mantell  (pars).     Geol.  Sussex,  p.  108,  1822. 
Spatamgus  complanatus,  Mantell.     Medals,  p.  355. 

Hemiaster  puxctatus,  (VOrbigny.     Pal.  Franc.  Ter.  Cret.,  pi.  886,  1854. 

—  MoRRisii,  Forbes.     Morris,   Cat.  Brit.  Foss.,   2nd  ed.,  p.  81, 

1854. 

—  —  Woodward.     Mem.  Geol.  Surv.,  decade  7,  pi.  ix,  1856. 

Diagnosis. — Test  oval,  polygonal,  or  cordiform,  inflated,  obtusely  rounded  before  and 
obliquely  truncated  behind,  sides  nodulated;  ambulacra  straight,  narrow,  moderately 
depressed,  anterior  pair  twice  as  long  as  posterior,  anteal  sulcus  short,  shallow,  dorsal ; 
apical  disc  excentral  backwards  ;  vertex  near  posterior  border,  which  is  flat  and  obliquely 
truncated  ;  periprocte  oval,  supra-marginal ;  base  convex,  with  a  slight  depression  near  the 
mouth,  which  is  bilabiate  and  opens  near  the  border;  fasciole  narrow,  distinct,  closely 
siu'TOundiug  the  petals. 

Dimensions. — Antero-posterior  diameter  one  inch  and  six  tenths ;  breadth  one  inch 
and  five  tenths  ;  height  one  inch. 

Descripfion. — This  Urchin  has  been  long  known  to  collectors  of  Cretaceous  fossils  by 
many  incorrect  names.  I  have  now  figured  it  with  ample  anatomical  details  for  the  first 
time,  which  for  the  future  will  make  it  impossible  to  mistake  it  for  any  other. 

The  outline  is  oval,  slightly  polygonal,  or  inclining  to  a  cordate  shape  ;  the  anteal  sulcus 
is  broad  and  obscure,  and  impresses  shghtly  the  anterior  border,  which  is  obtusely  rounded 
and  sometimes  flattened;  the  posterior  border  is  obliquely  and  flatly  truncated,  and 
slopes  at  an  angle  of  70°  ;  sometimes  this  border  becomes  slightly  concave  in  large  shells, 
and  it  is  conspicuously  so  in  three  specimens  in  my  collection. 

The  ambulacra!  petals  are  small  and  moderately  depressed,  the  anterior  incline 
45° ;  are  nearly  twice  as  long  as  the  posterior  pair  (fig.  1  a)  ;  the  poriferous  zones  are 
narrow,  and  the  pores  form  oblique  transverse  slits  in  them  ;  the  single  area  is  about  same 
length  as  the  anterior,  and  is  lodged  in  the  anteal  sulcus ;  there  are  from  twelve  to  fourteen 
pairs  of  pores  in  each  zone,  with  a  prominent  granule  between  each  of  the  pores  forming 
a  pair  (fig.  1  «) ;  the  anteal  sulcus  widens  out  and  disappears  at  the  anterior  border. 

The  inter-ambulacral  areas  present  a  remarkable  nodulated  appearance  in  this  species  ; 
in  each  area  there  are  two  rows  of  these  elevations ;  those  at  the  sides  are  seen  in 
fig.  1  a,  c ;  in  the  front  in  fig,  1  e;  and  the  back  fig.  1  d;  in  fig.  1  /t  the  appearance 


FROM  THE  LOWER  CHALK.  263 

these  nodules  present  is  admirably  shown  in  three  inter-ambulacral  plates  taken  from  the 
ambitus  and  magnified  three  diameters. 

The  peripetalous  fasciole  is  very  well  defined  in  this  species ;  it  passes  straight  from 
point  to  point  with  scarcely  any  curvature,  and  forms  a  bold  line  among  the  numerous 
tubercles ;  fig.  1  g  shows  this  structure. 

The  tubercles  are  small,  very  numerous,  and  set  irregularly  on  the  plates ;  they  are 
all  perforated,  and  raised  on  bosses  surrounded  by  well-defined  areolas ;  fig.  1  i  shows 
the  tubercles  on  the  upper  surface,  and  fig,  1  k  those  on  the  under  surface,  where  the 
larger  tubercles  have  the  bosses  crenulated  ;  besides  the  tubercles  the  entire  surface  of  the 
plates  is  closely  covered  with  miliary  granules. 

The  apical  disc  is  small  and  excentral,  the  four  genital  plates  are  perforated,  and  the 
antero-lateral  carries  the  spongy  body  (fig.  1  /) ;  the  five  ocular  plates  are  very  small,  as 
shown  in  fig.  1  f. 

The  oval  periprocte  occupies  the  upper  third  of  the  oblique  posterior  border  (fig.  1  «?), 
and  the  vertex  is  seen  rising  above  it  all,  as  shown  in  fig.  1  c,  d). 

The  base  is  convex  transversely  behind  the  mouth  (fig,  1  b,  c),  and  flat  before  that 
aperture.  The  basal  portions  of  the  ambulacral  areas,  especially  the  postero-lateral  pair, 
which  first  descend  backwards  towards  the  ambitus,  bend  round  the  border  forming  an 
obtuse  angle  there,  and  make  a  sinuous  coiu'se  to  the  mouth.  The  anterior  pair  and  the 
single  area  have  a  more  direct  course ;  the  basal  portions  of  the  postero-laterals  are 
destitute  of  tubercles  and  granules  (fig.  1  b). 

The  mouth-opening  is  situated  at  the  anterior  fourth  of  the  base ;  it  is  transversely 
arched  and  bilabiate,  the  lower  lip  being  the  most  prominent,  and  the  peristome  is 
surrounded  by  a  narrow  calcareous  band. 

The  tubercles  on  the  basal  portion  of  the  inter-ambulacrum  have  a  remarkable 
arrangement.  They  form  a  series  of  curved  rows  that  radiate  from  a  central  nodule 
near  the  posterior  border  and  from  a  kind  of  fan-shaped  tubercular  sculpture  between  the 
two  smooth  winding  paths  formed  by  the  sinuous  ambulacra  (fig.  b).  The  tubercles  on 
the  other  portions  of  the  inter-ambulacra  have  a  much  less  regular  arrangement. 

Affinities  caul  Differences. — This  species  resembles  //.  prunella,  Desor,  with  which  it 
has  been  confounded ;  it  diff'ers  from  that  species,  however,  in  being  much  larger,  less 
globular  and  inflated,  having  the  posterior  border  obliquely  truncated,  the  dorsum  much 
more  inclined,  and  having  the  tubercles  smaller  and  more  numerous,  and  the  inter- 
ambulacra  nodulated  around  the  sides. 

Locality  and  Stratit/rapJncal  Position. — This  species  is  found  only  in  the  Grey 
Chalk  near  Folkestone,  the  Lower  Chalk  at  Hamsey,  Sussex,  and  in  the  Grey  Chalk  of 
Ventnor,  Isle  of  Wight. 


264  HEMIASTER. 


Hemiaster  Bailti,  Forbes.     PL  LX,  fig.  2. 

ECHINOSPATANGUS,  Mantel!.     Geology  of  Susses,  p.  SG,  1822. 

IIOLASTEK  ABGILLACEUS,  Morris  (pars.),  Catalogue  Brit.  Foss.,  1st  ed.,  p.  54,  1843. 
Hemiaster  Bailyi,  Forbes.     Morris,  Catalogue,  2nd  ed.,  p.  81,  1854. 

—  Woodward.     Mem.  Geol.  Surv.,  decade  v,  1856. 

The  specimen  figured  in  this  plate  belongs  to  the  Museum  of  the  Royal  School  of  Mines, 
and  is  so  much  crushed  and  its  characters  defaced  that  I  am  unable  to  give  a  correct 
diagnosis  of  the  species,  and  now  figure  it  as  the  authentic  example  of  my  late  friend's 
species.  The  outline  figiu-e  and  general  contour  of  the  test  resemble  Eddnospatagus 
Murchisonianus.  "  The  peripetalous  fasciole  is  narrow,  distinct,  and  simple  in  contour, 
passing  from  end  to  end  of  the  ambulacral  petals  and  only  slightly  contracted  at  the 
sides.  The  surface  of  the  Echinidae  from  the  Gault  is  in  general  rough  with  nodular 
concretions  of  iron  pyrites  formed  upon  the  tubercles.  So  many  of  the  Blackdown 
fossils  are  identical  with  species  of  the  Folkestone  Gault  that  we  have  felt  considerable 
hesitation  in  admitting  as  specific  a  character  which  may  by  any  possibility  be  due  to  the 
mineral  condition  of  the  specimens." — Woodward. 

Localiiy  and  Stratif/rapldcal  Position. — Collected  from  the  Gault  at  Folkestone; 
the  type-specimen  I  have  figured  is  contained  in  the  Museum  of  the  Royal  School  of 
Mines. 


Hemiaster  asterias,  Forbes.     PI.  LX,  fig.  3. 

Hemiaster  asterias,  Forbes.     In  Morris,  Catalogue,  2nd  ed.,  p.  81,  1854. 
—  —         Woodward,  Mem.  Geol.  Surv.,  decade  v,  1856. 

The  type-specimen  I  have  figured  is  not  sufficiently  well  preserved  to  enable  me  to 
form  a  diagnosis  of  the  species.  The  vertex  appears  to  have  been  more  prominent  and 
removed  more  posteriorly  than  in  //.  Bailp,  and  the  dorsal  ambidacra  are  likewise 
rough  and  narrower  in  proportion  than  in  that  species. 

Locality  and  StratiyrapUcal  Position. — Collected  from  the  Gault  at  Folkestone, 
where  it  is  rare.  The  type-specimen  I  have  figured  belongs  to  the  Museum  of  the  Royal 
School  of  Mines,  Jermyn  Street. 


THE 


PALJIONTOGRAPHICAL   SOCIETY. 


INSTITUTED  MDCCCXLVII. 


VOLUME  EOE  1878. 


LONDON: 

MDCCOLXXTIII. 


MONOGRAPH 


ON   THE 


BRITISH     FOSSIL 


ECHINODERMATA 


TEOM 


THE  CRETACEOUS  FORMATIONS. 


THOMAS  WRIGHT,  M.D.,  F.R.S.  Edin.,  F.G.S., 

VICE-PRESIDENT  OF  THE  PAL«ONTOGBAPHICAL  SOCIETY;  CORRESl'ONDING  MEMBER  OF  THE    ROTAL  SOCIETY   OE  SCIENCES 

OF   LIEGE;   THE   SOCIETY  OF  NATURAL  SCIENCES  OP  NEUCHATEL;    VICE-PRESIDENT  OF  THE  COTTESWOLD 

naturalists'    field    CLUB;   CONSULTING    SURGEON   TO   THE    CHELTENHAM   HOSPITAL; 

AND  MEDICAL  OFFICER  OF  HEALTH  TO  THE  URBAN  SANITARY  DISTRICTS 

OF    CHELTENHAM,    CHAELTON-KINGS,   AND    LECKHAMPTON. 


VOLUME    FIRST. 

PART  EIGHTH. 
ON   THE   SPATANGID^   AND   ECHINOCORID^. 

Pages  265—300  ;  Plates  LXIIa,  LXIII— LXIX. 


LONDON; 

PRINTED   FOR  THE   PAL^EONTOGRAPHICAL   SOCIETY. 

1878. 


PRINTED    BY 
J.    E.    ADLABD,    BARTHOLOMEW   CLOSE. 


EPIASTER.  265 


Genus — Eptaster,  d' Orbi^ny,  1S5S. 
Spatangus  (pars),  Auctorum,     Micrasteb  (pars),  Agassis. 

Form  oblong  ;  test  more  or  less  elevated,  often  cordiform. 

Antero-  and  postero-lateral  pairs  of  ambulacra  petaloidal  and  lodged  in  depressions 
of  the  test;  the  anterior  are  longer  and  more  developed  than  the  posterior  pair. 
Poriferous  zones  equal  in  each  ambulacra,  composed  of  elongated  pores  shorter  in  the 
internal  than  in  the  external  rows. 

The  single  ambulacrum,  lodged  in  a  well-defined  anteal  sulcus,  is  composed  of  pores 
different  from  those  of  the  antero-  and  postero-lateral  pairs,  as  they  are  mostly  round 
and  disposed  in  pairs  set  widely  apart. 

The  apical  disc  is  composed  of  four  perforated  genital  and  five  ocular  plates. 

Peristome  near  the  anterior  border  and  strongly  bilabiate  ;  the  inferior  lip  thick  and 
prominent. 

Periprocte  round   or   oval,    situated   at  the   posterior   border,  often  opening  in   a 

distinct  area. 

No  fascioles. 

Tubercles  well  spaced  out,  unequal  in  size,  crenulated,  and  often  scrobiculated ;  inter- 
tubercular  area  covered  with  granules. 

The  Epiasters  have  been  long  confused  with  the  Micrasters,  which  they  resemble 
much,  but  differ  from  that  genus  in  the  absence  of  all  fascioles.  They  are  distinguished 
from  Echinospatagus  by  their  ambulacra,  which  are  in  the  form  of  enclosed  petals, 
by  their  poriferous  zones,  which  are  equal,  and  by  their  peristome,  which  is  markedly 
bilabiate. 


Epiastek  De  Loriolii,  JFriffht,  nov.  sp.     PI.  LIX,  figs.  1,  a—ff. 

MiCKASTER  LACCNOSUS,  Morris.     Catalogue  of  British  Fossils,  Isted.,  p.  55,  1843. 
Hemiaster  bucardium,  Woodward.     Mem.  Geol.  Surv.,  decade  v,  pi.  is,  notes,  1856. 

Diagnosis. — Test  large,  cordiform,  declining  anteriorly,  elevated  posteriorly ;  anteal 
sulcus  deep,  grooving  the  border ;  ambulacra  much  depressed.  Antero-laterals  curved 
slightly  forwards  and  outwards,  and  inclined  at  45° ;  postero-laterals  shorter,  curved 

34 


266  EPI  ASTER 

backwards  and  inwards,  and  inclined  at  30° ;  posterior  border  obliquely  truncated  ;  vent 
large,  oval,  supra-marginal ;  base  convex ;  mouth-opening  in  the  anterior  fourth  ;  peri- 
stome bilateral. 

Dimensions. — Length,  antero-posterior  diameter  two  inches  and  five  tenths ;  breadth, 
two  inches  and  five  tenths  ;  height,  one  inch  and  five  tenths. 

Description. — This  fine  large  Epiaster  has  been  long  known  to  geologists  as  a  fossil 
from  the  Upper  Greensand  of  Wiltshire,  as  I  have  detected  specimens  in  difierent 
collections  made  many  years  ago.  It  was  erroneously  identified  with  Parkinson's 
Spafanpus  lacunosus,  which  is  a  Maltese  specimen,  and  was  entered  in  the  first  edition  of 
Morris'  Catalogue  as  Micraster  lacunosus.  It  was  omitted  from  the  second  edition  of 
that  work,  and  described  by  Dr.  S.  P.  Woodward  as  Hemiaster  bucardium,  from  his 
belief  that  it  agreed  with  Goldfuss'  figure. 

The  test  is  large  and  cordiform  in  middle  growth,  and  round  and  tumid  with  age, 
when  its  width  and  length  are  about  equal.  The  vertex  is  at  a  point  between  the 
terminal  portions  of  the  postero-lateral  ambulacra,  from  whence  its  horizontal  profile 
slopes  gently  towards  the  anterior  border  and  backwards  to  the  abruptly  truncated 
posterior  border. 

The  anteal  sulcus  is  deep  and  narrow,  with  nearly  vertical  walls ;  it  grooves  deeply 
the  anterior  border,  fig.  1  a,  and  extends  from  the  disc  to  the  mouth,  fig.  1  e. 

The  pores  are  small,  biserial,  closely  set  together,  and  limited  to  the  upper  half  of  the 
area,  with  a  prominent  granule  between  the  two  pores  forming  a  pair. 

The  ambulacra  are  much  depressed,  circumscribed,  and  unequal  in  length  and 
inchnation ;  the  antero-lateral  are  one  third  longer  than  the  postero-lateral  pair. 

The  poriferous  zones  are  wide,  of  unequal  length,  and  formed  of  transversely  elon- 
gated pores,  those  in  the  posterior  zone  of  the  antero-lateral  pair  are  the  longest  and  there 
the  pores  are  widest  apart. 

There  is  no  true  peripetalous  fascicle,  and  the  naked  line  which  Mr.  Bone  mistook 
for  this  structure  and  figured  as  such  appears  to  have  been  produced  by  friction  on  the 
sutures  of  the  large  inter-ambulacral  plates  forming  the  peripetalous  area  added  to  a 
certain  local  baldness  at  the  terminal  portions  of  the  depressed  ambulacra,  so  that 
referring  to  Plate  LIX  the  student  must  please  delete  the  peripetalous  naked  line  in 
fig.  1  a,  c,  d,  e,  f ;  in  all  other  respects  the  various  figures  given  on  this  plate  are 
admirable  delineations  of  the  form  and  structure  of  this  fine  Epiaster. 

The  apical  disc  is  central ;  it  has  four  perforated  ovarial  plates,  a  very  small  spongy 
body,  and  five  oculars  with  distinct  orbits. 

The  numerous  small  tubercles  are  arranged  in  rows  in  quincuncial  order  on  the 
plates  and  the  mterspaces  are  covered  besides  with  abundant  granulations.      Fig.  1/ 
represents  three  inter-ambulacral  plates,  the  terminal  portion  of  an  ambulacrum,  with 
its  poriferous  zones,  magnified  three  diameters  in  order  to  illustrate  this  portion  of  the 
anatomy  of  the  test. 


FROM  THE  WHITE  CHALK. 


267 


Affinities  and  Differences. — The  wide  test,  deep  ambulacra,  and  inclined  upper  surface 
distinguish  this  Urchin  from  all  its  congeners ;  and  likewise  from  the  Micrasters  with 
which  others  have  been  often  confounded. 

I  dedicate  this  fine  species  to  my  esteemed  friend  M.  De  Loriol,  the  learned  author  of 
the  '  fichinologie  Helvetique/  whose  assiduous  studies  in  Palaeontology  have  borne  such 
ample  fruits. 

Locality  and  Stratigrapldcal  Position.  This  species  has  been  collected  from  the 
Upper  Greensand,  near  Warminster  and  Devizes,  Wilts. 


Epiaster  gibbus,  Lamarck,  1816.     PI.  LXIH,  fig.  1,  a — k. 

Spatangus  gibbus, 


—  COB-ANGUINUM, 

—  GIBBUS, 


Lamarck.      Animaux   sans   Vertebres,   t.   iii, 

p.  32,  1816. 
Deslo7tff  champs.        Enc.    Method.,    p.    689, 

pi.  156,  figs.  4— 6,  1824. 
Gold/uss.     Petr.  Germanise,  tab.  xlviii,  fig.  4, 

p.  155,  1824. 
Defrance.     Diet.  Sc.  Nat.,  t.  1,  p.  94,  1827. 
Woodward.     Geol.  of  Norfolk,  pi.  v,  fig.  8, 

1833. 
De  Blainville.    Manuel  d'Actin.,  pp.  203,  653, 

1834. 
Grateloup.      Oursins    Foss.    (Dax),    p.     71, 

1836. 
Desmoulins.     Etudes  sur  les  Echinides,  p.  402, 

1837. 
Edwards.     Anim.  sans  Verteb.,  t.  iii,  p.  331, 

1840. 
Agassiz.     Catal.  Syst.,  p.  129,  1847. 
Hebert.  Etudes  sur  les  Terr.  Cretaces  ;  Mem. 

Soc.  Geol.  France,  2e  ser.,  t.  v,  pi.  xxix, 

fig.  16,  1854. 
Desor.     Synopsis  Echid.  Foss.,  p.  365,  1858. 
Forbes  (pars).     Mem.   Geol.  Surv.,  dec.  iii, 

pi.  X,  1850. 
Forbes.     In  Dixon's  Geol.  of  Sussex,  p.  342, 

pi.  xxiv,  figs.  5,  6,  1850. 
COE-ANGUINUM  var.  GIBBUS,  Morris.     Brit.  Foss.,  2nd  ed.,  p.  83, 1854. 

—  d  Orbigmj  (pars).     Paleont.  Fran9aise  Terr. 

Cret.,  t.  vi,  p.  207,  1855. 


MiCKASTER  CORDATUS, 


—  GIBBUS, 

—  COR-ANGUINUM, 

—  GIBBUS, 


Diagnosis. — Test  cordiform,  very  high,  and  almost  conical ;  sides  convex  and 
carinated.  Ambulacra  slightly  depressed  ;  anteal  sulcus  shallow  above  and  grooving  the 
anterior  border  ;  posterior  margin  acuminated  and  truncated  obliquely  inwards.      Vent 


268  EPIASTER 

round,  supra-marginal ;  base  slightly  convex  transversely ;  mouth-opening  very  near 
the  border,  bilabiate,  with  prominent  under  lip ;  apical  disc  nearly  central,  and  placed 
before  the  vertex. 

Dimensions. — Height,  1-j^  inch  ;  length,  2^^  inch. 

Description. — There  has  been  so  much  difference  of  opinion  about  this  Urchin  that  I 
have  given  full  details  of  the  anatomy  of  its  test  in  PI.  LXIII. 

Lamarck,  yvho  first  described  it,  has  the  following  diagnosis : — "  Sp.  cordato- 
abbreviatus,  convexus,  subgibbosus,  antice  retusus  ;  vertice  elato ;  ambulacris  quinis, 
duplicato-biporosis ;  ano  ovato ;"  and  refers  to  the  figure  in  the  '  Encyclopedic 
Methodique,'  pi.  156,  figs.  4 — 6,  as  the  type  of  the  form.  Goldfuss  gave  in  his 
'  Petrefacta '  excellent  figures  and  an  accurate  description.  Woodward  sketched  a  fair 
outline  of  it  in  his  '  Geology  of  Norfolk,'  but  mistook  it  for  the  common  Chalk  species 
Micraster  cor-anguinum.  Desmoulins,  De  Blainville,  Deshayes,  Grateloup,  and  Desor, 
all  retained  the  species  as  established  by  Lamarck.  My  late  esteemed  colleague. 
Professor  E.  Forbes,  upheld  Woodward's  mistake,  and  mentioned  it  as  a  variety  of 
Micraster  cor-anguinum  in  the  'Memoirs  of  the  Geological  Survey,'  Decade  III,  PI.  10, 
whilst  oddly  enough  he  had  previously  described  it  correctly  in  his  account  of  the 
Echinodermata  in  Dixon's  '  Geology  of  Sussex.'  D'Orbigny  in  his  '  Paleontologie 
Frangaise '  groups  M.  gibbus  with  M.  cor-anguinum,  and  perpetuates  the  old  confusion 
I  have  pointed  out. 

If  we  admit  that  the  structure  and  disposition  of  a  fasciole  oxfascioles  form  characters 
of  sufficient  importance  for  the  establishment  of  generic  groups  among  the  Sjjafa7igidcB, 
then,  indeed,  the  Urchin  under  consideration  is  not  only  specifically  but  generically 
distinct  from  Micraster  cor-anguinum,  for,  whereas  all  true  Micrasters  have  a  subanal 
fasciole,  forming  a  ring  placed  around  the  base  of  the  posterior  border,  one  half  of 
which  embraces  the  border,  the  other  half  the  base,  the  Urchin  before  us  has  no 
fasciole  whatever ;  and  this  anatomical  fact  has  been  altogether  overlooked  both  by  Forbes 
and  d'Orbigny,  otherwise  they  would  not  have  confused  ^z'Wws  with  cor-anguinum. 

The  build  of  this  Urchin  differs  from  M.  cor-anguinum  in  having  a  flattened  base,  an 
angular  ambitus,  and  a  pyramidal  upper  surface,  with  steeply-inclined  sides,  the  anterior 
portion  sloping  at  an  angle  of  from  40°  to  50°,  the  posterior  from  25°  to  30°,  and  the 
lateral  sides  35°.  In  half  a  dozen  good  typical  specimens  these  measurements  represent 
a  fair  average.     PI.  LXllI,  fig.  1,  c,  d,  e. 

The  ambulacral  areas  are  narrow,  and  their  petaloidal  portions  not  much  depressed, 
fig.  1  a,  c,  d,  e ;  the  antero-lateral  being  one  third  longer  than  the  postero-lateral  pair. 
The  poriferous  zones  of  the  petals  consist  of  a  pair  of  holes,  the  inner  being  rounder 
than  those  in  the  outer  line,  and  they  are  connected  by  a  slight  depression  in  the  plates, 
fig.  1  g.  Beyond  the  petals  the  zones  diverge  ;  and  in  the  anterior  pair  I  have  traced 
the  holes  to  the  ambitus,  in  the  posterior  pair  they  have  disappeared.  The  anteal  sulcus 
is  feebly  marked,  and  the  single  petal  shorter  than  the  anterior  pair ;  in  the  petaloid 


FROM  THE  WHITE   CHALK.  269 

section  it  contains  about  20  pairs  of  holes  in  each  zone,  and  in  the  non-petaloidal  portion 
of  this  area  the  small  pairs  of  pores  can  be  distinctly  traced  to  the  ambitus  and  onward 
to  the  mouth-opening,  fig.  1  e,  h.  The  ambulacral  plates  in  the  petaloidal  portions  of 
the  areas  are  elongated  and  flat  in  the  single  area,  and  short,  convex,  and  tumid  in  the 
antero-  and  postero-lateral  pairs.  There  are  several  miliary  granules  on  the  plates  in  the 
single  arc  and  only  solitary  granules  on  the  convex  surface  of  those  in  the  pairs. 

The  inter-ambulacral  areas  are  formed  of  very  large  plates  (fig.  1  a,  c,  d,  e),  which 
on  the  upper  surfa